diff --git a/devtools/gerrit/gerrit-oauth-provider/BUILD b/devtools/gerrit/gerrit-oauth-provider/BUILD
index c0b0b56..413ef46 100644
--- a/devtools/gerrit/gerrit-oauth-provider/BUILD
+++ b/devtools/gerrit/gerrit-oauth-provider/BUILD
@@ -1,3 +1,4 @@
+load("@rules_java//java:defs.bzl", "java_library")
 load("//devtools/gerrit/gerrit-oauth-provider/tools/bzl:junit.bzl", "junit_tests")
 load(
     "//devtools/gerrit/gerrit-oauth-provider/tools/bzl:plugin.bzl",
@@ -19,7 +20,8 @@
     resources = glob(["src/main/resources/**/*"]),
     deps = [
         "@commons-codec//jar:neverlink",
-        "@scribe//jar",
+        "@jackson-databind//jar",
+        "@scribejava-core//jar",
     ],
 )
 
@@ -29,6 +31,7 @@
     tags = ["oauth"],
     deps = [
         ":gerrit-oauth-provider__plugin_test_deps",
+        "@scribejava-core//jar",
     ],
 )
 
@@ -38,6 +41,5 @@
     visibility = ["//visibility:public"],
     exports = PLUGIN_DEPS + PLUGIN_TEST_DEPS + [
         ":gerrit-oauth-provider__plugin",
-        "@scribe//jar",
     ],
 )
diff --git a/devtools/gerrit/gerrit-oauth-provider/README.md b/devtools/gerrit/gerrit-oauth-provider/README.md
index 414eef6..0fe5acd 100644
--- a/devtools/gerrit/gerrit-oauth-provider/README.md
+++ b/devtools/gerrit/gerrit-oauth-provider/README.md
@@ -16,6 +16,7 @@
 * [GitLab](https://about.gitlab.com/)
 * [Google](https://developers.google.com/identity/protocols/OAuth2)
 * [Keycloak](http://www.keycloak.org/)
+* [LemonLDAP::NG](https://lemonldap-ng.org)
 * [Office365](https://docs.microsoft.com/en-us/azure/active-directory/develop/active-directory-v2-protocols)
 
 See the [Wiki](https://github.com/davido/gerrit-oauth-provider/wiki) what it can do for you.
@@ -40,7 +41,7 @@
 Install
 -------
 
-Copy the `bazel-genfiles/oauth.jar` to
+Copy the `bazel-bin/oauth.jar` to
 `$gerrit_site/plugins` and re-run init to configure it:
 
 ```
diff --git a/devtools/gerrit/gerrit-oauth-provider/external_plugin_deps.bzl b/devtools/gerrit/gerrit-oauth-provider/external_plugin_deps.bzl
index e560344..5279435 100644
--- a/devtools/gerrit/gerrit-oauth-provider/external_plugin_deps.bzl
+++ b/devtools/gerrit/gerrit-oauth-provider/external_plugin_deps.bzl
@@ -1,10 +1,24 @@
-load("//tools/bzl:maven_jar.bzl", "maven_jar")
+load("//devtools/gerrit/gerrit-oauth-provider/tools/bzl:maven_jar.bzl", "maven_jar")
 
 def external_plugin_deps(omit_commons_codec = True):
+    JACKSON_VERS = "2.10.2"
     maven_jar(
-        name = "scribe",
-        artifact = "org.scribe:scribe:1.3.7",
-        sha1 = "583921bed46635d9f529ef5f14f7c9e83367bc6e",
+        name = "scribejava-core",
+        artifact = "com.github.scribejava:scribejava-core:6.9.0",
+        sha1 = "ed761f450d8382f75787e8fee9ae52e7ec768747",
+    )
+    maven_jar(
+        name = "jackson-annotations",
+        artifact = "com.fasterxml.jackson.core:jackson-annotations:" + JACKSON_VERS,
+        sha1 = "3a13b6105946541b8d4181a0506355b5fae63260",
+    )
+    maven_jar(
+        name = "jackson-databind",
+        artifact = "com.fasterxml.jackson.core:jackson-databind:" + JACKSON_VERS,
+        sha1 = "0528de95f198afafbcfb0c09d2e43b6e0ea663ec",
+        deps = [
+            "@jackson-annotations//jar",
+        ],
     )
     if not omit_commons_codec:
         maven_jar(
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/AirVantageApi.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/AirVantageApi.java
index 02f4bd5..0426162 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/AirVantageApi.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/AirVantageApi.java
@@ -14,43 +14,23 @@
 
 package com.googlesource.gerrit.plugins.oauth;
 
-import static java.lang.String.format;
-
-import org.scribe.builder.api.DefaultApi20;
-import org.scribe.extractors.AccessTokenExtractor;
-import org.scribe.extractors.JsonTokenExtractor;
-import org.scribe.model.OAuthConfig;
-import org.scribe.model.Verb;
-import org.scribe.oauth.OAuthService;
+import com.github.scribejava.core.builder.api.DefaultApi20;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignature;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignatureURIQueryParameter;
 
 public class AirVantageApi extends DefaultApi20 {
-
-  private static final String AUTHORIZE_URL =
-      "https://eu.airvantage.net/api/oauth/authorize?client_id=%s&response_type=code";
-  private static final String ACCESS_TOKEN_ENDPOINT = "https://eu.airvantage.net/api/oauth/token";
-
   @Override
-  public String getAuthorizationUrl(OAuthConfig config) {
-    return format(AUTHORIZE_URL, config.getApiKey());
+  public String getAuthorizationBaseUrl() {
+    return "https://eu.airvantage.net/api/oauth/authorize";
   }
 
   @Override
   public String getAccessTokenEndpoint() {
-    return ACCESS_TOKEN_ENDPOINT;
+    return "https://eu.airvantage.net/api/oauth/token";
   }
 
   @Override
-  public Verb getAccessTokenVerb() {
-    return Verb.POST;
-  }
-
-  @Override
-  public AccessTokenExtractor getAccessTokenExtractor() {
-    return new JsonTokenExtractor();
-  }
-
-  @Override
-  public OAuthService createService(OAuthConfig config) {
-    return new OAuth20ServiceImpl(this, config);
+  public BearerSignature getBearerSignature() {
+    return BearerSignatureURIQueryParameter.instance();
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/AirVantageOAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/AirVantageOAuthService.java
index a1ec591..0af9316 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/AirVantageOAuthService.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/AirVantageOAuthService.java
@@ -18,6 +18,12 @@
 import static javax.servlet.http.HttpServletResponse.SC_OK;
 import static org.slf4j.LoggerFactory.getLogger;
 
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.model.OAuthRequest;
+import com.github.scribejava.core.model.Response;
+import com.github.scribejava.core.model.Verb;
+import com.github.scribejava.core.oauth.OAuth20Service;
 import com.google.common.base.CharMatcher;
 import com.google.gerrit.extensions.annotations.PluginName;
 import com.google.gerrit.extensions.auth.oauth.OAuthServiceProvider;
@@ -33,13 +39,7 @@
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import java.io.IOException;
-import org.scribe.builder.ServiceBuilder;
-import org.scribe.model.OAuthRequest;
-import org.scribe.model.Response;
-import org.scribe.model.Token;
-import org.scribe.model.Verb;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
+import java.util.concurrent.ExecutionException;
 import org.slf4j.Logger;
 
 @Singleton
@@ -49,7 +49,7 @@
   private static final String AV_PROVIDER_PREFIX = "airvantage-oauth:";
   private static final String PROTECTED_RESOURCE_URL =
       "https://eu.airvantage.net/api/v1/users/current";
-  private final OAuthService service;
+  private final OAuth20Service service;
 
   @Inject
   AirVantageOAuthService(
@@ -60,44 +60,47 @@
     String canonicalWebUrl = CharMatcher.is('/').trimTrailingFrom(urlProvider.get()) + "/";
 
     service =
-        new ServiceBuilder()
-            .provider(AirVantageApi.class)
-            .apiKey(cfg.getString(InitOAuth.CLIENT_ID))
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
             .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
             .callback(canonicalWebUrl + "oauth")
-            .build();
+            .build(new AirVantageApi());
   }
 
   @Override
   public OAuthUserInfo getUserInfo(OAuthToken token) throws IOException {
     OAuthRequest request = new OAuthRequest(Verb.GET, PROTECTED_RESOURCE_URL);
-    Token t = new Token(token.getToken(), token.getSecret(), token.getRaw());
+    OAuth2AccessToken t = new OAuth2AccessToken(token.getToken(), token.getRaw());
     service.signRequest(t, request);
-    Response response = request.send();
-    if (response.getCode() != SC_OK) {
-      throw new IOException(
-          String.format(
-              "Status %s (%s) for request %s",
-              response.getCode(), response.getBody(), request.getUrl()));
-    }
-    JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
-    if (log.isDebugEnabled()) {
-      log.debug("User info response: {}", response.getBody());
-    }
-    if (userJson.isJsonObject()) {
-      JsonObject jsonObject = userJson.getAsJsonObject();
-      JsonElement id = jsonObject.get("uid");
-      if (id == null || id.isJsonNull()) {
-        throw new IOException("Response doesn't contain uid field");
+
+    JsonElement userJson = null;
+    try (Response response = service.execute(request)) {
+      if (response.getCode() != SC_OK) {
+        throw new IOException(
+            String.format(
+                "Status %s (%s) for request %s",
+                response.getCode(), response.getBody(), request.getUrl()));
       }
-      JsonElement email = jsonObject.get("email");
-      JsonElement name = jsonObject.get("name");
-      return new OAuthUserInfo(
-          AV_PROVIDER_PREFIX + id.getAsString(),
-          null,
-          email.getAsString(),
-          name.getAsString(),
-          id.getAsString());
+      userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
+      if (log.isDebugEnabled()) {
+        log.debug("User info response: {}", response.getBody());
+      }
+      if (userJson.isJsonObject()) {
+        JsonObject jsonObject = userJson.getAsJsonObject();
+        JsonElement id = jsonObject.get("uid");
+        if (id == null || id.isJsonNull()) {
+          throw new IOException("Response doesn't contain uid field");
+        }
+        JsonElement email = jsonObject.get("email");
+        JsonElement name = jsonObject.get("name");
+        return new OAuthUserInfo(
+            AV_PROVIDER_PREFIX + id.getAsString(),
+            null,
+            email.getAsString(),
+            name.getAsString(),
+            id.getAsString());
+      }
+    } catch (ExecutionException | InterruptedException e) {
+      throw new RuntimeException("Cannot retrieve user info resource", e);
     }
 
     throw new IOException(String.format("Invalid JSON '%s': not a JSON Object", userJson));
@@ -105,14 +108,20 @@
 
   @Override
   public OAuthToken getAccessToken(OAuthVerifier rv) {
-    Verifier vi = new Verifier(rv.getValue());
-    Token to = service.getAccessToken(null, vi);
-    return new OAuthToken(to.getToken(), to.getSecret(), to.getRawResponse());
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
   }
 
   @Override
   public String getAuthorizationUrl() {
-    return service.getAuthorizationUrl(null);
+    return service.getAuthorizationUrl();
   }
 
   @Override
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/BitbucketApi.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/BitbucketApi.java
index de0f5ea..06e92bc 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/BitbucketApi.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/BitbucketApi.java
@@ -14,137 +14,23 @@
 
 package com.googlesource.gerrit.plugins.oauth;
 
-import static com.google.gerrit.json.OutputFormat.JSON;
-import static java.lang.String.format;
-import static javax.servlet.http.HttpServletResponse.SC_OK;
-import static org.scribe.model.OAuthConstants.ACCESS_TOKEN;
-import static org.scribe.model.OAuthConstants.CODE;
-
-import com.google.common.io.BaseEncoding;
-import com.google.gson.JsonElement;
-import com.google.gson.JsonObject;
-import org.scribe.builder.api.DefaultApi20;
-import org.scribe.exceptions.OAuthException;
-import org.scribe.extractors.AccessTokenExtractor;
-import org.scribe.model.OAuthConfig;
-import org.scribe.model.OAuthRequest;
-import org.scribe.model.Response;
-import org.scribe.model.Token;
-import org.scribe.model.Verb;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
+import com.github.scribejava.core.builder.api.DefaultApi20;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignature;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignatureURIQueryParameter;
 
 public class BitbucketApi extends DefaultApi20 {
-
-  private static final String AUTHORIZE_URL =
-      "https://bitbucket.org/site/oauth2/authorize?client_id=%s&response_type=code";
-  private static final String ACCESS_TOKEN_ENDPOINT =
-      "https://bitbucket.org/site/oauth2/access_token";
-
-  public BitbucketApi() {}
-
   @Override
-  public String getAuthorizationUrl(OAuthConfig config) {
-    return format(AUTHORIZE_URL, config.getApiKey());
+  public String getAuthorizationBaseUrl() {
+    return "https://bitbucket.org/site/oauth2/authorize";
   }
 
   @Override
   public String getAccessTokenEndpoint() {
-    return ACCESS_TOKEN_ENDPOINT;
+    return "https://bitbucket.org/site/oauth2/access_token";
   }
 
   @Override
-  public Verb getAccessTokenVerb() {
-    return Verb.POST;
-  }
-
-  @Override
-  public OAuthService createService(OAuthConfig config) {
-    return new BitbucketOAuthService(this, config);
-  }
-
-  @Override
-  public AccessTokenExtractor getAccessTokenExtractor() {
-    return new BitbucketTokenExtractor();
-  }
-
-  private static final class BitbucketOAuthService implements OAuthService {
-    private static final String VERSION = "2.0";
-
-    private static final String GRANT_TYPE = "grant_type";
-    private static final String GRANT_TYPE_VALUE = "authorization_code";
-
-    private final DefaultApi20 api;
-    private final OAuthConfig config;
-
-    private BitbucketOAuthService(DefaultApi20 api, OAuthConfig config) {
-      this.config = config;
-      this.api = api;
-    }
-
-    @Override
-    public Token getAccessToken(Token token, Verifier verifier) {
-      OAuthRequest request =
-          new OAuthRequest(api.getAccessTokenVerb(), api.getAccessTokenEndpoint());
-      request.addHeader("Authorization", prepareAuthorizationHeaderValue());
-      request.addBodyParameter(GRANT_TYPE, GRANT_TYPE_VALUE);
-      request.addBodyParameter(CODE, verifier.getValue());
-      Response response = request.send();
-      if (response.getCode() == SC_OK) {
-        Token t = api.getAccessTokenExtractor().extract(response.getBody());
-        return new Token(t.getToken(), config.getApiSecret());
-      }
-
-      throw new OAuthException(
-          String.format(
-              "Error response received: %s, HTTP status: %s",
-              response.getBody(), response.getCode()));
-    }
-
-    private String prepareAuthorizationHeaderValue() {
-      String value = String.format("%s:%s", config.getApiKey(), config.getApiSecret());
-      String valueBase64 = BaseEncoding.base64().encode(value.getBytes());
-      return String.format("Basic %s", valueBase64);
-    }
-
-    @Override
-    public Token getRequestToken() {
-      throw new UnsupportedOperationException(
-          "Unsupported operation, please use 'getAuthorizationUrl' and redirect your users there");
-    }
-
-    @Override
-    public String getVersion() {
-      return VERSION;
-    }
-
-    @Override
-    public void signRequest(Token token, OAuthRequest request) {
-      request.addQuerystringParameter(ACCESS_TOKEN, token.getToken());
-    }
-
-    @Override
-    public String getAuthorizationUrl(Token token) {
-      return api.getAuthorizationUrl(config);
-    }
-  }
-
-  private static final class BitbucketTokenExtractor implements AccessTokenExtractor {
-
-    @Override
-    public Token extract(String response) {
-      JsonElement json = JSON.newGson().fromJson(response, JsonElement.class);
-      if (json.isJsonObject()) {
-        JsonObject jsonObject = json.getAsJsonObject();
-        JsonElement id = jsonObject.get(ACCESS_TOKEN);
-        if (id == null || id.isJsonNull()) {
-          throw new OAuthException("Response doesn't contain 'access_token' field");
-        }
-        JsonElement accessToken = jsonObject.get(ACCESS_TOKEN);
-        return new Token(accessToken.getAsString(), "");
-      }
-
-      throw new OAuthException(String.format("Invalid JSON '%s': not a JSON Object", json));
-    }
+  public BearerSignature getBearerSignature() {
+    return BearerSignatureURIQueryParameter.instance();
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/BitbucketOAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/BitbucketOAuthService.java
index c1524e9..accf586 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/BitbucketOAuthService.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/BitbucketOAuthService.java
@@ -18,6 +18,12 @@
 import static javax.servlet.http.HttpServletResponse.SC_OK;
 import static org.slf4j.LoggerFactory.getLogger;
 
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.model.OAuthRequest;
+import com.github.scribejava.core.model.Response;
+import com.github.scribejava.core.model.Verb;
+import com.github.scribejava.core.oauth.OAuth20Service;
 import com.google.common.base.CharMatcher;
 import com.google.gerrit.extensions.annotations.PluginName;
 import com.google.gerrit.extensions.auth.oauth.OAuthServiceProvider;
@@ -33,13 +39,7 @@
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import java.io.IOException;
-import org.scribe.builder.ServiceBuilder;
-import org.scribe.model.OAuthRequest;
-import org.scribe.model.Response;
-import org.scribe.model.Token;
-import org.scribe.model.Verb;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
+import java.util.concurrent.ExecutionException;
 import org.slf4j.Logger;
 
 @Singleton
@@ -49,7 +49,7 @@
   private static final String BITBUCKET_PROVIDER_PREFIX = "bitbucket-oauth:";
   private static final String PROTECTED_RESOURCE_URL = "https://bitbucket.org/api/1.0/user/";
   private final boolean fixLegacyUserId;
-  private final OAuthService service;
+  private final OAuth20Service service;
 
   @Inject
   BitbucketOAuthService(
@@ -61,46 +61,50 @@
     String canonicalWebUrl = CharMatcher.is('/').trimTrailingFrom(urlProvider.get()) + "/";
     fixLegacyUserId = cfg.getBoolean(InitOAuth.FIX_LEGACY_USER_ID, false);
     service =
-        new ServiceBuilder()
-            .provider(BitbucketApi.class)
-            .apiKey(cfg.getString(InitOAuth.CLIENT_ID))
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
             .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
             .callback(canonicalWebUrl + "oauth")
-            .build();
+            .build(new BitbucketApi());
   }
 
   @Override
   public OAuthUserInfo getUserInfo(OAuthToken token) throws IOException {
     OAuthRequest request = new OAuthRequest(Verb.GET, PROTECTED_RESOURCE_URL);
-    Token t = new Token(token.getToken(), token.getSecret(), token.getRaw());
+    OAuth2AccessToken t = new OAuth2AccessToken(token.getToken(), token.getRaw());
     service.signRequest(t, request);
-    Response response = request.send();
-    if (response.getCode() != SC_OK) {
-      throw new IOException(
-          String.format(
-              "Status %s (%s) for request %s",
-              response.getCode(), response.getBody(), request.getUrl()));
-    }
-    JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
-    if (log.isDebugEnabled()) {
-      log.debug("User info response: {}", response.getBody());
-    }
-    if (userJson.isJsonObject()) {
-      JsonObject jsonObject = userJson.getAsJsonObject();
-      JsonObject userObject = jsonObject.getAsJsonObject("user");
-      if (userObject == null || userObject.isJsonNull()) {
-        throw new IOException("Response doesn't contain 'user' field");
-      }
-      JsonElement usernameElement = userObject.get("username");
-      String username = usernameElement.getAsString();
 
-      JsonElement displayName = jsonObject.get("display_name");
-      return new OAuthUserInfo(
-          BITBUCKET_PROVIDER_PREFIX + username,
-          username,
-          null,
-          displayName == null || displayName.isJsonNull() ? null : displayName.getAsString(),
-          fixLegacyUserId ? username : null);
+    JsonElement userJson = null;
+    try (Response response = service.execute(request)) {
+
+      if (response.getCode() != SC_OK) {
+        throw new IOException(
+            String.format(
+                "Status %s (%s) for request %s",
+                response.getCode(), response.getBody(), request.getUrl()));
+      }
+      userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
+      if (log.isDebugEnabled()) {
+        log.debug("User info response: {}", response.getBody());
+      }
+      if (userJson.isJsonObject()) {
+        JsonObject jsonObject = userJson.getAsJsonObject();
+        JsonObject userObject = jsonObject.getAsJsonObject("user");
+        if (userObject == null || userObject.isJsonNull()) {
+          throw new IOException("Response doesn't contain 'user' field");
+        }
+        JsonElement usernameElement = userObject.get("username");
+        String username = usernameElement.getAsString();
+
+        JsonElement displayName = jsonObject.get("display_name");
+        return new OAuthUserInfo(
+            BITBUCKET_PROVIDER_PREFIX + username,
+            username,
+            null,
+            displayName == null || displayName.isJsonNull() ? null : displayName.getAsString(),
+            fixLegacyUserId ? username : null);
+      }
+    } catch (ExecutionException | InterruptedException e) {
+      throw new RuntimeException("Cannot retrieve user info resource", e);
     }
 
     throw new IOException(String.format("Invalid JSON '%s': not a JSON Object", userJson));
@@ -108,14 +112,20 @@
 
   @Override
   public OAuthToken getAccessToken(OAuthVerifier rv) {
-    Verifier vi = new Verifier(rv.getValue());
-    Token to = service.getAccessToken(null, vi);
-    return new OAuthToken(to.getToken(), to.getSecret(), to.getRawResponse());
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
   }
 
   @Override
   public String getAuthorizationUrl() {
-    return service.getAuthorizationUrl(null);
+    return service.getAuthorizationUrl();
   }
 
   @Override
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/CasApi.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/CasApi.java
index 76d4011..450549f 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/CasApi.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/CasApi.java
@@ -14,15 +14,15 @@
 
 package com.googlesource.gerrit.plugins.oauth;
 
-import org.scribe.builder.api.DefaultApi20;
-import org.scribe.model.OAuthConfig;
-import org.scribe.model.Verb;
-import org.scribe.oauth.OAuthService;
-import org.scribe.utils.OAuthEncoder;
+import com.github.scribejava.core.builder.api.DefaultApi20;
+import com.github.scribejava.core.extractors.OAuth2AccessTokenExtractor;
+import com.github.scribejava.core.extractors.TokenExtractor;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignature;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignatureURIQueryParameter;
 
 public class CasApi extends DefaultApi20 {
-  private static final String AUTHORIZE_URL =
-      "%s/oauth2.0/authorize?response_type=code&client_id=%s&redirect_uri=%s";
+  private static final String AUTHORIZE_URL = "%s/oauth2.0/authorize";
 
   private final String rootUrl;
 
@@ -36,18 +36,17 @@
   }
 
   @Override
-  public String getAuthorizationUrl(OAuthConfig config) {
-    return String.format(
-        AUTHORIZE_URL, rootUrl, config.getApiKey(), OAuthEncoder.encode(config.getCallback()));
+  public String getAuthorizationBaseUrl() {
+    return String.format(AUTHORIZE_URL, rootUrl);
   }
 
   @Override
-  public Verb getAccessTokenVerb() {
-    return Verb.POST;
+  public BearerSignature getBearerSignature() {
+    return BearerSignatureURIQueryParameter.instance();
   }
 
   @Override
-  public OAuthService createService(OAuthConfig config) {
-    return new OAuth20ServiceImpl(this, config);
+  public TokenExtractor<OAuth2AccessToken> getAccessTokenExtractor() {
+    return OAuth2AccessTokenExtractor.instance();
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/CasOAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/CasOAuthService.java
index e90c5b3..d76769a 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/CasOAuthService.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/CasOAuthService.java
@@ -16,6 +16,12 @@
 
 import static com.google.gerrit.json.OutputFormat.JSON;
 
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.model.OAuthRequest;
+import com.github.scribejava.core.model.Response;
+import com.github.scribejava.core.model.Verb;
+import com.github.scribejava.core.oauth.OAuth20Service;
 import com.google.common.base.CharMatcher;
 import com.google.gerrit.extensions.annotations.PluginName;
 import com.google.gerrit.extensions.auth.oauth.OAuthServiceProvider;
@@ -30,16 +36,12 @@
 import com.google.gson.JsonObject;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
+import com.google.inject.ProvisionException;
 import com.google.inject.Singleton;
 import java.io.IOException;
+import java.net.URI;
+import java.util.concurrent.ExecutionException;
 import javax.servlet.http.HttpServletResponse;
-import org.scribe.builder.ServiceBuilder;
-import org.scribe.model.OAuthRequest;
-import org.scribe.model.Response;
-import org.scribe.model.Token;
-import org.scribe.model.Verb;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -52,7 +54,7 @@
 
   private final String rootUrl;
   private final boolean fixLegacyUserId;
-  private final OAuthService service;
+  private final OAuth20Service service;
 
   @Inject
   CasOAuthService(
@@ -61,83 +63,88 @@
       @CanonicalWebUrl Provider<String> urlProvider) {
     PluginConfig cfg = cfgFactory.getFromGerritConfig(pluginName + CONFIG_SUFFIX);
     rootUrl = cfg.getString(InitOAuth.ROOT_URL);
+    if (!URI.create(rootUrl).isAbsolute()) {
+      throw new ProvisionException("Root URL must be absolute URL");
+    }
     String canonicalWebUrl = CharMatcher.is('/').trimTrailingFrom(urlProvider.get()) + "/";
     fixLegacyUserId = cfg.getBoolean(InitOAuth.FIX_LEGACY_USER_ID, false);
     service =
-        new ServiceBuilder()
-            .provider(new CasApi(rootUrl))
-            .apiKey(cfg.getString(InitOAuth.CLIENT_ID))
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
             .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
             .callback(canonicalWebUrl + "oauth")
-            .build();
+            .build(new CasApi(rootUrl));
   }
 
   @Override
   public OAuthUserInfo getUserInfo(OAuthToken token) throws IOException {
-    final String protectedResourceUrl = String.format(PROTECTED_RESOURCE_URL, rootUrl);
-    OAuthRequest request = new OAuthRequest(Verb.GET, protectedResourceUrl);
-    Token t = new Token(token.getToken(), token.getSecret(), token.getRaw());
+    OAuthRequest request =
+        new OAuthRequest(Verb.GET, String.format(PROTECTED_RESOURCE_URL, rootUrl));
+    OAuth2AccessToken t = new OAuth2AccessToken(token.getToken(), token.getRaw());
     service.signRequest(t, request);
 
-    Response response = request.send();
-    if (response.getCode() != HttpServletResponse.SC_OK) {
-      throw new IOException(
-          String.format(
-              "Status %s (%s) for request %s",
-              response.getCode(), response.getBody(), request.getUrl()));
-    }
-
-    if (log.isDebugEnabled()) {
-      log.debug("User info response: {}", response.getBody());
-    }
-
-    JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
-    if (!userJson.isJsonObject()) {
-      throw new IOException(String.format("Invalid JSON '%s': not a JSON Object", userJson));
-    }
-    JsonObject jsonObject = userJson.getAsJsonObject();
-
-    JsonElement id = jsonObject.get("id");
-    if (id == null || id.isJsonNull()) {
-      throw new IOException(String.format("CAS response missing id: %s", response.getBody()));
-    }
-
-    JsonElement attrListJson = jsonObject.get("attributes");
-    if (attrListJson == null) {
-      throw new IOException(
-          String.format("CAS response missing attributes: %s", response.getBody()));
-    }
-
-    String email = null, name = null, login = null;
-
-    if (attrListJson.isJsonArray()) {
-      // It is possible for CAS to be configured to not return any attributes (email, name, login),
-      // in which case,
-      // CAS returns an empty JSON object "attributes":{}, rather than "null" or an empty JSON array
-      // "attributes": []
-
-      JsonArray attrJson = attrListJson.getAsJsonArray();
-      for (JsonElement elem : attrJson) {
-        if (elem == null || !elem.isJsonObject()) {
-          throw new IOException(String.format("Invalid JSON '%s': not a JSON Object", elem));
-        }
-        JsonObject obj = elem.getAsJsonObject();
-
-        String property = getStringElement(obj, "email");
-        if (property != null) email = property;
-        property = getStringElement(obj, "name");
-        if (property != null) name = property;
-        property = getStringElement(obj, "login");
-        if (property != null) login = property;
+    try (Response response = service.execute(request)) {
+      if (response.getCode() != HttpServletResponse.SC_OK) {
+        throw new IOException(
+            String.format(
+                "Status %s (%s) for request %s",
+                response.getCode(), response.getBody(), request.getUrl()));
       }
-    }
 
-    return new OAuthUserInfo(
-        CAS_PROVIDER_PREFIX + id.getAsString(),
-        login,
-        email,
-        name,
-        fixLegacyUserId ? id.getAsString() : null);
+      if (log.isDebugEnabled()) {
+        log.debug("User info response: {}", response.getBody());
+      }
+
+      JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
+      if (!userJson.isJsonObject()) {
+        throw new IOException(String.format("Invalid JSON '%s': not a JSON Object", userJson));
+      }
+      JsonObject jsonObject = userJson.getAsJsonObject();
+
+      JsonElement id = jsonObject.get("id");
+      if (id == null || id.isJsonNull()) {
+        throw new IOException(String.format("CAS response missing id: %s", response.getBody()));
+      }
+
+      JsonElement attrListJson = jsonObject.get("attributes");
+      if (attrListJson == null) {
+        throw new IOException(
+            String.format("CAS response missing attributes: %s", response.getBody()));
+      }
+
+      String email = null, name = null, login = null;
+      if (attrListJson.isJsonArray()) {
+        // It is possible for CAS to be configured to not return any attributes (email, name,
+        // login),
+        // in which case,
+        // CAS returns an empty JSON object "attributes":{}, rather than "null" or an empty JSON
+        // array
+        // "attributes": []
+
+        JsonArray attrJson = attrListJson.getAsJsonArray();
+        for (JsonElement elem : attrJson) {
+          if (elem == null || !elem.isJsonObject()) {
+            throw new IOException(String.format("Invalid JSON '%s': not a JSON Object", elem));
+          }
+          JsonObject obj = elem.getAsJsonObject();
+
+          String property = getStringElement(obj, "email");
+          if (property != null) email = property;
+          property = getStringElement(obj, "name");
+          if (property != null) name = property;
+          property = getStringElement(obj, "login");
+          if (property != null) login = property;
+        }
+      }
+
+      return new OAuthUserInfo(
+          CAS_PROVIDER_PREFIX + id.getAsString(),
+          login,
+          email,
+          name,
+          fixLegacyUserId ? id.getAsString() : null);
+    } catch (ExecutionException | InterruptedException e) {
+      throw new RuntimeException("Cannot retrieve user info resource", e);
+    }
   }
 
   private String getStringElement(JsonObject o, String name) {
@@ -149,14 +156,20 @@
 
   @Override
   public OAuthToken getAccessToken(OAuthVerifier rv) {
-    Verifier vi = new Verifier(rv.getValue());
-    Token to = service.getAccessToken(null, vi);
-    return new OAuthToken(to.getToken(), to.getSecret(), to.getRawResponse());
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
   }
 
   @Override
   public String getAuthorizationUrl() {
-    return service.getAuthorizationUrl(null);
+    return service.getAuthorizationUrl();
   }
 
   @Override
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/DexApi.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/DexApi.java
index 2386e24..1f2510e 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/DexApi.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/DexApi.java
@@ -14,18 +14,13 @@
 
 package com.googlesource.gerrit.plugins.oauth;
 
-import org.scribe.builder.api.DefaultApi20;
-import org.scribe.extractors.AccessTokenExtractor;
-import org.scribe.extractors.JsonTokenExtractor;
-import org.scribe.model.OAuthConfig;
-import org.scribe.model.Verb;
-import org.scribe.oauth.OAuthService;
-import org.scribe.utils.OAuthEncoder;
+import com.github.scribejava.core.builder.api.DefaultApi20;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignature;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignatureURIQueryParameter;
 
 public class DexApi extends DefaultApi20 {
 
-  private static final String AUTHORIZE_URL =
-      "%s/dex/auth?client_id=%s&response_type=code&redirect_uri=%s&scope=%s";
+  private static final String AUTHORIZE_URL = "%s/dex/auth";
 
   private final String rootUrl;
 
@@ -34,13 +29,8 @@
   }
 
   @Override
-  public String getAuthorizationUrl(OAuthConfig config) {
-    return String.format(
-        AUTHORIZE_URL,
-        rootUrl,
-        config.getApiKey(),
-        OAuthEncoder.encode(config.getCallback()),
-        config.getScope().replaceAll(" ", "+"));
+  public String getAuthorizationBaseUrl() {
+    return String.format(AUTHORIZE_URL, rootUrl);
   }
 
   @Override
@@ -49,17 +39,7 @@
   }
 
   @Override
-  public Verb getAccessTokenVerb() {
-    return Verb.POST;
-  }
-
-  @Override
-  public OAuthService createService(OAuthConfig config) {
-    return new OAuth20ServiceImpl(this, config);
-  }
-
-  @Override
-  public AccessTokenExtractor getAccessTokenExtractor() {
-    return new JsonTokenExtractor();
+  public BearerSignature getBearerSignature() {
+    return BearerSignatureURIQueryParameter.instance();
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/DexOAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/DexOAuthService.java
index 255d394..009ee31 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/DexOAuthService.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/DexOAuthService.java
@@ -16,6 +16,9 @@
 
 import static com.google.gerrit.json.OutputFormat.JSON;
 
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.oauth.OAuth20Service;
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Preconditions;
 import com.google.gerrit.extensions.annotations.PluginName;
@@ -30,20 +33,22 @@
 import com.google.gson.JsonObject;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
+import com.google.inject.ProvisionException;
 import com.google.inject.Singleton;
 import java.io.IOException;
+import java.net.URI;
+import java.util.concurrent.ExecutionException;
 import org.apache.commons.codec.binary.Base64;
-import org.scribe.builder.ServiceBuilder;
-import org.scribe.model.Token;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 @Singleton
 public class DexOAuthService implements OAuthServiceProvider {
+  private static final Logger log = LoggerFactory.getLogger(DexOAuthService.class);
 
   static final String CONFIG_SUFFIX = "-dex-oauth";
   private static final String DEX_PROVIDER_PREFIX = "dex-oauth:";
-  private final OAuthService service;
+  private final OAuth20Service service;
   private final String rootUrl;
   private final String domain;
   private final String serviceName;
@@ -57,17 +62,18 @@
     String canonicalWebUrl = CharMatcher.is('/').trimTrailingFrom(urlProvider.get()) + "/";
 
     rootUrl = cfg.getString(InitOAuth.ROOT_URL);
+    if (!URI.create(rootUrl).isAbsolute()) {
+      throw new ProvisionException("Root URL must be absolute URL");
+    }
     domain = cfg.getString(InitOAuth.DOMAIN, null);
     serviceName = cfg.getString(InitOAuth.SERVICE_NAME, "Dex OAuth2");
 
     service =
-        new ServiceBuilder()
-            .provider(new DexApi(rootUrl))
-            .apiKey(cfg.getString(InitOAuth.CLIENT_ID))
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
             .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
-            .scope("openid profile email offline_access")
+            .defaultScope("openid profile email offline_access")
             .callback(canonicalWebUrl + "oauth")
-            .build();
+            .build(new DexApi(rootUrl));
   }
 
   private String parseJwt(String input) {
@@ -115,14 +121,20 @@
 
   @Override
   public OAuthToken getAccessToken(OAuthVerifier rv) {
-    Verifier vi = new Verifier(rv.getValue());
-    Token to = service.getAccessToken(null, vi);
-    return new OAuthToken(to.getToken(), to.getSecret(), to.getRawResponse());
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
   }
 
   @Override
   public String getAuthorizationUrl() {
-    return service.getAuthorizationUrl(null);
+    return service.getAuthorizationUrl();
   }
 
   @Override
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Facebook2Api.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Facebook2Api.java
index a547bfb..96f4636 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Facebook2Api.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Facebook2Api.java
@@ -14,12 +14,23 @@
 
 package com.googlesource.gerrit.plugins.oauth;
 
-import org.scribe.builder.api.FacebookApi;
-import org.scribe.extractors.AccessTokenExtractor;
+import com.github.scribejava.core.builder.api.DefaultApi20;
+import com.github.scribejava.core.oauth2.clientauthentication.ClientAuthentication;
+import com.github.scribejava.core.oauth2.clientauthentication.RequestBodyAuthenticationScheme;
 
-public class Facebook2Api extends FacebookApi {
+public class Facebook2Api extends DefaultApi20 {
   @Override
-  public AccessTokenExtractor getAccessTokenExtractor() {
-    return OAuth2AccessTokenJsonExtractor.instance();
+  protected String getAuthorizationBaseUrl() {
+    return "https://www.facebook.com/dialog/oauth";
+  }
+
+  @Override
+  public String getAccessTokenEndpoint() {
+    return "https://graph.facebook.com/oauth/access_token";
+  }
+
+  @Override
+  public ClientAuthentication getClientAuthentication() {
+    return RequestBodyAuthenticationScheme.instance();
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/FacebookOAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/FacebookOAuthService.java
index bc5818a..7682410 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/FacebookOAuthService.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/FacebookOAuthService.java
@@ -16,6 +16,12 @@
 
 import static com.google.gerrit.json.OutputFormat.JSON;
 
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.model.OAuthRequest;
+import com.github.scribejava.core.model.Response;
+import com.github.scribejava.core.model.Verb;
+import com.github.scribejava.core.oauth.OAuth20Service;
 import com.google.common.base.CharMatcher;
 import com.google.gerrit.extensions.annotations.PluginName;
 import com.google.gerrit.extensions.auth.oauth.OAuthServiceProvider;
@@ -31,14 +37,8 @@
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import java.io.IOException;
+import java.util.concurrent.ExecutionException;
 import javax.servlet.http.HttpServletResponse;
-import org.scribe.builder.ServiceBuilder;
-import org.scribe.model.OAuthRequest;
-import org.scribe.model.Response;
-import org.scribe.model.Token;
-import org.scribe.model.Verb;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -52,7 +52,7 @@
   private static final String SCOPE = "email";
   private static final String FIELDS_QUERY = "fields";
   private static final String FIELDS = "email,name";
-  private final OAuthService service;
+  private final OAuth20Service service;
 
   @Inject
   FacebookOAuthService(
@@ -64,53 +64,55 @@
     String canonicalWebUrl = CharMatcher.is('/').trimTrailingFrom(urlProvider.get()) + "/";
 
     service =
-        new ServiceBuilder()
-            .provider(Facebook2Api.class)
-            .apiKey(cfg.getString(InitOAuth.CLIENT_ID))
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
             .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
             .callback(canonicalWebUrl + "oauth")
-            .scope(SCOPE)
-            .build();
+            .defaultScope(SCOPE)
+            .build(new Facebook2Api());
   }
 
   @Override
   public OAuthUserInfo getUserInfo(OAuthToken token) throws IOException {
     OAuthRequest request = new OAuthRequest(Verb.GET, PROTECTED_RESOURCE_URL);
-    Token t = new Token(token.getToken(), token.getSecret(), token.getRaw());
     request.addQuerystringParameter(FIELDS_QUERY, FIELDS);
+    OAuth2AccessToken t = new OAuth2AccessToken(token.getToken(), token.getRaw());
     service.signRequest(t, request);
-    Response response = request.send();
 
-    if (response.getCode() != HttpServletResponse.SC_OK) {
-      throw new IOException(
-          String.format(
-              "Status %s (%s) for request %s",
-              response.getCode(), response.getBody(), request.getUrl()));
-    }
-    JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
-
-    if (log.isDebugEnabled()) {
-      log.debug("User info response: {}", response.getBody());
-    }
-    if (userJson.isJsonObject()) {
-      JsonObject jsonObject = userJson.getAsJsonObject();
-      JsonElement id = jsonObject.get("id");
-      if (id == null || id.isJsonNull()) {
-        throw new IOException("Response doesn't contain id field");
+    JsonElement userJson = null;
+    try (Response response = service.execute(request)) {
+      if (response.getCode() != HttpServletResponse.SC_OK) {
+        throw new IOException(
+            String.format(
+                "Status %s (%s) for request %s",
+                response.getCode(), response.getBody(), request.getUrl()));
       }
-      JsonElement email = jsonObject.get("email");
-      JsonElement name = jsonObject.get("name");
-      // Heads up!
-      // Lets keep `login` equal to `email`, since `username` field is
-      // deprecated for Facebook API versions v2.0 and higher
-      JsonElement login = jsonObject.get("email");
+      userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
 
-      return new OAuthUserInfo(
-          FACEBOOK_PROVIDER_PREFIX + id.getAsString(),
-          login == null || login.isJsonNull() ? null : login.getAsString(),
-          email == null || email.isJsonNull() ? null : email.getAsString(),
-          name == null || name.isJsonNull() ? null : name.getAsString(),
-          null);
+      if (log.isDebugEnabled()) {
+        log.debug("User info response: {}", response.getBody());
+      }
+      if (userJson.isJsonObject()) {
+        JsonObject jsonObject = userJson.getAsJsonObject();
+        JsonElement id = jsonObject.get("id");
+        if (id == null || id.isJsonNull()) {
+          throw new IOException("Response doesn't contain id field");
+        }
+        JsonElement email = jsonObject.get("email");
+        JsonElement name = jsonObject.get("name");
+        // Heads up!
+        // Lets keep `login` equal to `email`, since `username` field is
+        // deprecated for Facebook API versions v2.0 and higher
+        JsonElement login = jsonObject.get("email");
+
+        return new OAuthUserInfo(
+            FACEBOOK_PROVIDER_PREFIX + id.getAsString(),
+            login == null || login.isJsonNull() ? null : login.getAsString(),
+            email == null || email.isJsonNull() ? null : email.getAsString(),
+            name == null || name.isJsonNull() ? null : name.getAsString(),
+            null);
+      }
+    } catch (ExecutionException | InterruptedException e) {
+      throw new RuntimeException("Cannot retrieve user info resource", e);
     }
 
     throw new IOException(String.format("Invalid JSON '%s': not a JSON Object", userJson));
@@ -118,16 +120,20 @@
 
   @Override
   public OAuthToken getAccessToken(OAuthVerifier rv) {
-    Verifier vi = new Verifier(rv.getValue());
-    Token to = service.getAccessToken(null, vi);
-    OAuthToken result = new OAuthToken(to.getToken(), to.getSecret(), to.getRawResponse());
-
-    return result;
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
   }
 
   @Override
   public String getAuthorizationUrl() {
-    return service.getAuthorizationUrl(null);
+    return service.getAuthorizationUrl();
   }
 
   @Override
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitHub2Api.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitHub2Api.java
index 4b8419b..477eadf 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitHub2Api.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitHub2Api.java
@@ -14,22 +14,32 @@
 
 package com.googlesource.gerrit.plugins.oauth;
 
-import org.scribe.builder.api.DefaultApi20;
-import org.scribe.model.OAuthConfig;
-import org.scribe.utils.OAuthEncoder;
+import com.github.scribejava.core.builder.api.DefaultApi20;
+import com.github.scribejava.core.extractors.OAuth2AccessTokenExtractor;
+import com.github.scribejava.core.extractors.TokenExtractor;
+import com.github.scribejava.core.model.OAuth2AccessToken;
 
 public class GitHub2Api extends DefaultApi20 {
-  private static final String AUTHORIZE_URL =
-      "https://github.com/login/oauth/authorize?client_id=%s&redirect_uri=%s";
+  private static final String AUTHORIZE_URL = "%slogin/oauth/authorize";
 
-  @Override
-  public String getAccessTokenEndpoint() {
-    return "https://github.com/login/oauth/access_token";
+  private final String rootUrl;
+
+  public GitHub2Api(String rootUrl) {
+    this.rootUrl = rootUrl;
   }
 
   @Override
-  public String getAuthorizationUrl(OAuthConfig config) {
-    return String.format(
-        AUTHORIZE_URL, config.getApiKey(), OAuthEncoder.encode(config.getCallback()));
+  public String getAccessTokenEndpoint() {
+    return String.format("%slogin/oauth/access_token", rootUrl);
+  }
+
+  @Override
+  protected String getAuthorizationBaseUrl() {
+    return String.format(AUTHORIZE_URL, rootUrl);
+  }
+
+  @Override
+  public TokenExtractor<OAuth2AccessToken> getAccessTokenExtractor() {
+    return OAuth2AccessTokenExtractor.instance();
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitHubOAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitHubOAuthService.java
index 1c73c0e..12643b2 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitHubOAuthService.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitHubOAuthService.java
@@ -16,6 +16,12 @@
 
 import static com.google.gerrit.json.OutputFormat.JSON;
 
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.model.OAuthRequest;
+import com.github.scribejava.core.model.Response;
+import com.github.scribejava.core.model.Verb;
+import com.github.scribejava.core.oauth.OAuth20Service;
 import com.google.common.base.CharMatcher;
 import com.google.gerrit.extensions.annotations.PluginName;
 import com.google.gerrit.extensions.auth.oauth.OAuthServiceProvider;
@@ -31,14 +37,8 @@
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import java.io.IOException;
+import java.util.concurrent.ExecutionException;
 import javax.servlet.http.HttpServletResponse;
-import org.scribe.builder.ServiceBuilder;
-import org.scribe.model.OAuthRequest;
-import org.scribe.model.Response;
-import org.scribe.model.Token;
-import org.scribe.model.Verb;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -47,11 +47,14 @@
   private static final Logger log = LoggerFactory.getLogger(GitHubOAuthService.class);
   static final String CONFIG_SUFFIX = "-github-oauth";
   private static final String GITHUB_PROVIDER_PREFIX = "github-oauth:";
-  private static final String PROTECTED_RESOURCE_URL = "https://api.github.com/user";
+  private static final String GITHUB_API_ENDPOINT_URL = "https://api.github.com/";
+  private static final String GHE_API_ENDPOINT_URL = "%sapi/v3/";
+  static final String GITHUB_ROOT_URL = "https://github.com/";
+  private final String rootUrl;
 
-  private static final String SCOPE = "user:email";
+  static final String SCOPE = "user:email";
   private final boolean fixLegacyUserId;
-  private final OAuthService service;
+  private final OAuth20Service service;
 
   @Inject
   GitHubOAuthService(
@@ -61,47 +64,64 @@
     PluginConfig cfg = cfgFactory.getFromGerritConfig(pluginName + CONFIG_SUFFIX);
     String canonicalWebUrl = CharMatcher.is('/').trimTrailingFrom(urlProvider.get()) + "/";
     fixLegacyUserId = cfg.getBoolean(InitOAuth.FIX_LEGACY_USER_ID, false);
+    rootUrl =
+        CharMatcher.is('/').trimTrailingFrom(cfg.getString(InitOAuth.ROOT_URL, GITHUB_ROOT_URL))
+            + "/";
+
     service =
-        new ServiceBuilder()
-            .provider(GitHub2Api.class)
-            .apiKey(cfg.getString(InitOAuth.CLIENT_ID))
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
             .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
             .callback(canonicalWebUrl + "oauth")
-            .scope(SCOPE)
-            .build();
+            .defaultScope(SCOPE)
+            .build(new GitHub2Api(rootUrl));
+  }
+
+  private String getApiUrl() {
+    return GITHUB_ROOT_URL.equals(rootUrl)
+        ? GITHUB_API_ENDPOINT_URL
+        : String.format(GHE_API_ENDPOINT_URL, rootUrl);
+  }
+
+  private String getProtectedResourceUrl() {
+    return getApiUrl() + "user";
   }
 
   @Override
   public OAuthUserInfo getUserInfo(OAuthToken token) throws IOException {
-    OAuthRequest request = new OAuthRequest(Verb.GET, PROTECTED_RESOURCE_URL);
-    Token t = new Token(token.getToken(), token.getSecret(), token.getRaw());
+    OAuthRequest request = new OAuthRequest(Verb.GET, getProtectedResourceUrl());
+    OAuth2AccessToken t = new OAuth2AccessToken(token.getToken(), token.getRaw());
     service.signRequest(t, request);
-    Response response = request.send();
-    if (response.getCode() != HttpServletResponse.SC_OK) {
-      throw new IOException(
-          String.format(
-              "Status %s (%s) for request %s",
-              response.getCode(), response.getBody(), request.getUrl()));
-    }
-    JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
-    if (log.isDebugEnabled()) {
-      log.debug("User info response: {}", response.getBody());
-    }
-    if (userJson.isJsonObject()) {
-      JsonObject jsonObject = userJson.getAsJsonObject();
-      JsonElement id = jsonObject.get("id");
-      if (id == null || id.isJsonNull()) {
-        throw new IOException("Response doesn't contain id field");
+
+    JsonElement userJson = null;
+    try (Response response = service.execute(request)) {
+      if (response.getCode() != HttpServletResponse.SC_OK) {
+        throw new IOException(
+            String.format(
+                "Status %s (%s) for request %s",
+                response.getCode(), response.getBody(), request.getUrl()));
       }
-      JsonElement email = jsonObject.get("email");
-      JsonElement name = jsonObject.get("name");
-      JsonElement login = jsonObject.get("login");
-      return new OAuthUserInfo(
-          GITHUB_PROVIDER_PREFIX + id.getAsString(),
-          login == null || login.isJsonNull() ? null : login.getAsString(),
-          email == null || email.isJsonNull() ? null : email.getAsString(),
-          name == null || name.isJsonNull() ? null : name.getAsString(),
-          fixLegacyUserId ? id.getAsString() : null);
+      userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
+      if (log.isDebugEnabled()) {
+        log.debug("User info response: {}", response.getBody());
+      }
+      if (userJson.isJsonObject()) {
+        JsonObject jsonObject = userJson.getAsJsonObject();
+        JsonElement id = jsonObject.get("id");
+        if (id == null || id.isJsonNull()) {
+          throw new IOException("Response doesn't contain id field");
+        }
+        JsonElement email = jsonObject.get("email");
+        JsonElement name = jsonObject.get("name");
+        JsonElement login = jsonObject.get("login");
+        return new OAuthUserInfo(
+            GITHUB_PROVIDER_PREFIX + id.getAsString(),
+            login == null || login.isJsonNull() ? null : login.getAsString(),
+            email == null || email.isJsonNull() ? null : email.getAsString(),
+            name == null || name.isJsonNull() ? null : name.getAsString(),
+            fixLegacyUserId ? id.getAsString() : null);
+      }
+    } catch (ExecutionException | InterruptedException e) {
+      throw new RuntimeException("Cannot retrieve user info resource", e);
     }
 
     throw new IOException(String.format("Invalid JSON '%s': not a JSON Object", userJson));
@@ -109,15 +129,20 @@
 
   @Override
   public OAuthToken getAccessToken(OAuthVerifier rv) {
-    Verifier vi = new Verifier(rv.getValue());
-    Token to = service.getAccessToken(null, vi);
-    OAuthToken result = new OAuthToken(to.getToken(), to.getSecret(), to.getRawResponse());
-    return result;
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
   }
 
   @Override
   public String getAuthorizationUrl() {
-    return service.getAuthorizationUrl(null);
+    return service.getAuthorizationUrl();
   }
 
   @Override
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitLabApi.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitLabApi.java
index db0851f..ca88d05 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitLabApi.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitLabApi.java
@@ -14,15 +14,12 @@
 
 package com.googlesource.gerrit.plugins.oauth;
 
-import org.scribe.builder.api.DefaultApi20;
-import org.scribe.extractors.AccessTokenExtractor;
-import org.scribe.model.OAuthConfig;
-import org.scribe.model.Verb;
-import org.scribe.oauth.OAuthService;
+import com.github.scribejava.core.builder.api.DefaultApi20;
+import com.github.scribejava.core.oauth2.clientauthentication.ClientAuthentication;
+import com.github.scribejava.core.oauth2.clientauthentication.RequestBodyAuthenticationScheme;
 
 public class GitLabApi extends DefaultApi20 {
-  private static final String AUTHORIZE_URL =
-      "%s/oauth/authorize?client_id=%s&response_type=code&redirect_uri=%s";
+  private static final String AUTHORIZE_URL = "%s/oauth/authorize";
 
   private final String rootUrl;
 
@@ -31,8 +28,8 @@
   }
 
   @Override
-  public String getAuthorizationUrl(OAuthConfig config) {
-    return String.format(AUTHORIZE_URL, rootUrl, config.getApiKey(), config.getCallback());
+  public String getAuthorizationBaseUrl() {
+    return String.format(AUTHORIZE_URL, rootUrl);
   }
 
   @Override
@@ -41,17 +38,7 @@
   }
 
   @Override
-  public Verb getAccessTokenVerb() {
-    return Verb.POST;
-  }
-
-  @Override
-  public OAuthService createService(OAuthConfig config) {
-    return new OAuth20ServiceImpl(this, config);
-  }
-
-  @Override
-  public AccessTokenExtractor getAccessTokenExtractor() {
-    return OAuth2AccessTokenJsonExtractor.instance();
+  public ClientAuthentication getClientAuthentication() {
+    return RequestBodyAuthenticationScheme.instance();
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitLabOAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitLabOAuthService.java
index ed4c456..57eb94b 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitLabOAuthService.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GitLabOAuthService.java
@@ -18,6 +18,12 @@
 import static javax.servlet.http.HttpServletResponse.SC_OK;
 import static org.slf4j.LoggerFactory.getLogger;
 
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.model.OAuthRequest;
+import com.github.scribejava.core.model.Response;
+import com.github.scribejava.core.model.Verb;
+import com.github.scribejava.core.oauth.OAuth20Service;
 import com.google.common.base.CharMatcher;
 import com.google.gerrit.extensions.annotations.PluginName;
 import com.google.gerrit.extensions.auth.oauth.OAuthServiceProvider;
@@ -31,15 +37,11 @@
 import com.google.gson.JsonObject;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
+import com.google.inject.ProvisionException;
 import com.google.inject.Singleton;
 import java.io.IOException;
-import org.scribe.builder.ServiceBuilder;
-import org.scribe.model.OAuthRequest;
-import org.scribe.model.Response;
-import org.scribe.model.Token;
-import org.scribe.model.Verb;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
+import java.net.URI;
+import java.util.concurrent.ExecutionException;
 import org.slf4j.Logger;
 
 @Singleton
@@ -48,7 +50,7 @@
   static final String CONFIG_SUFFIX = "-gitlab-oauth";
   private static final String PROTECTED_RESOURCE_URL = "%s/api/v3/user";
   private static final String GITLAB_PROVIDER_PREFIX = "gitlab-oauth:";
-  private final OAuthService service;
+  private final OAuth20Service service;
   private final String rootUrl;
 
   @Inject
@@ -59,59 +61,69 @@
     PluginConfig cfg = cfgFactory.getFromGerritConfig(pluginName + CONFIG_SUFFIX);
     String canonicalWebUrl = CharMatcher.is('/').trimTrailingFrom(urlProvider.get()) + "/";
     rootUrl = cfg.getString(InitOAuth.ROOT_URL);
+    if (!URI.create(rootUrl).isAbsolute()) {
+      throw new ProvisionException("Root URL must be absolute URL");
+    }
     service =
-        new ServiceBuilder()
-            .provider(new GitLabApi(rootUrl))
-            .apiKey(cfg.getString(InitOAuth.CLIENT_ID))
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
             .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
             .callback(canonicalWebUrl + "oauth")
-            .build();
+            .build(new GitLabApi(rootUrl));
   }
 
   @Override
   public OAuthUserInfo getUserInfo(OAuthToken token) throws IOException {
-    final String protectedResourceUrl = String.format(PROTECTED_RESOURCE_URL, rootUrl);
-    OAuthRequest request = new OAuthRequest(Verb.GET, protectedResourceUrl);
-    Token t = new Token(token.getToken(), token.getSecret(), token.getRaw());
+    OAuthRequest request =
+        new OAuthRequest(Verb.GET, String.format(PROTECTED_RESOURCE_URL, rootUrl));
+    OAuth2AccessToken t = new OAuth2AccessToken(token.getToken(), token.getRaw());
     service.signRequest(t, request);
 
-    Response response = request.send();
-    if (response.getCode() != SC_OK) {
-      throw new IOException(
-          String.format(
-              "Status %s (%s) for request %s",
-              response.getCode(), response.getBody(), request.getUrl()));
+    try (Response response = service.execute(request)) {
+      if (response.getCode() != SC_OK) {
+        throw new IOException(
+            String.format(
+                "Status %s (%s) for request %s",
+                response.getCode(), response.getBody(), request.getUrl()));
+      }
+      JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
+      if (log.isDebugEnabled()) {
+        log.debug("User info response: {}", response.getBody());
+      }
+      JsonObject jsonObject = userJson.getAsJsonObject();
+      if (jsonObject == null || jsonObject.isJsonNull()) {
+        throw new IOException("Response doesn't contain 'user' field" + jsonObject);
+      }
+      JsonElement id = jsonObject.get("id");
+      JsonElement username = jsonObject.get("username");
+      JsonElement email = jsonObject.get("email");
+      JsonElement name = jsonObject.get("name");
+      return new OAuthUserInfo(
+          GITLAB_PROVIDER_PREFIX + id.getAsString(),
+          username == null || username.isJsonNull() ? null : username.getAsString(),
+          email == null || email.isJsonNull() ? null : email.getAsString(),
+          name == null || name.isJsonNull() ? null : name.getAsString(),
+          null);
+    } catch (ExecutionException | InterruptedException e) {
+      throw new RuntimeException("Cannot retrieve user info resource", e);
     }
-    JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
-    if (log.isDebugEnabled()) {
-      log.debug("User info response: {}", response.getBody());
-    }
-    JsonObject jsonObject = userJson.getAsJsonObject();
-    if (jsonObject == null || jsonObject.isJsonNull()) {
-      throw new IOException("Response doesn't contain 'user' field" + jsonObject);
-    }
-    JsonElement id = jsonObject.get("id");
-    JsonElement username = jsonObject.get("username");
-    JsonElement email = jsonObject.get("email");
-    JsonElement name = jsonObject.get("name");
-    return new OAuthUserInfo(
-        GITLAB_PROVIDER_PREFIX + id.getAsString(),
-        username == null || username.isJsonNull() ? null : username.getAsString(),
-        email == null || email.isJsonNull() ? null : email.getAsString(),
-        name == null || name.isJsonNull() ? null : name.getAsString(),
-        null);
   }
 
   @Override
   public OAuthToken getAccessToken(OAuthVerifier rv) {
-    Verifier vi = new Verifier(rv.getValue());
-    Token to = service.getAccessToken(null, vi);
-    return new OAuthToken(to.getToken(), to.getSecret(), to.getRawResponse());
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
   }
 
   @Override
   public String getAuthorizationUrl() {
-    return service.getAuthorizationUrl(null);
+    return service.getAuthorizationUrl();
   }
 
   @Override
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Google2Api.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Google2Api.java
index 88c640d..4f2eed2 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Google2Api.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Google2Api.java
@@ -14,50 +14,16 @@
 
 package com.googlesource.gerrit.plugins.oauth;
 
-import static org.scribe.utils.OAuthEncoder.encode;
+import com.github.scribejava.core.builder.api.DefaultApi20;
 
-import org.scribe.builder.api.DefaultApi20;
-import org.scribe.extractors.AccessTokenExtractor;
-import org.scribe.model.OAuthConfig;
-import org.scribe.model.Verb;
-import org.scribe.oauth.OAuthService;
-import org.scribe.utils.Preconditions;
-
-// Source: https://github.com/FeedTheCoffers/scribe-java-extras
-// License: Apache 2
-// https://github.com/FeedTheCoffers/scribe-java-extras/blob/master/pom.xml
 public class Google2Api extends DefaultApi20 {
-  private static final String AUTHORIZE_URL =
-      "https://accounts.google.com/o/oauth2/auth?response_type=code&client_id=%s&redirect_uri=%s&scope=%s";
-
   @Override
   public String getAccessTokenEndpoint() {
-    return "https://accounts.google.com/o/oauth2/token";
+    return "https://www.googleapis.com/oauth2/v4/token";
   }
 
   @Override
-  public String getAuthorizationUrl(OAuthConfig config) {
-    Preconditions.checkValidUrl(
-        config.getCallback(), "Must provide a valid url as callback. Google does not support OOB");
-    Preconditions.checkEmptyString(
-        config.getScope(), "Must provide a valid value as scope. Google does not support no scope");
-
-    return String.format(
-        AUTHORIZE_URL, config.getApiKey(), encode(config.getCallback()), encode(config.getScope()));
-  }
-
-  @Override
-  public Verb getAccessTokenVerb() {
-    return Verb.POST;
-  }
-
-  @Override
-  public OAuthService createService(OAuthConfig config) {
-    return new OAuth20ServiceImpl(this, config);
-  }
-
-  @Override
-  public AccessTokenExtractor getAccessTokenExtractor() {
-    return OAuth2AccessTokenJsonExtractor.instance();
+  public String getAuthorizationBaseUrl() {
+    return "https://accounts.google.com/o/oauth2/auth";
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GoogleOAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GoogleOAuthService.java
index d6fcacf..b63ba33 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GoogleOAuthService.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/GoogleOAuthService.java
@@ -16,6 +16,12 @@
 
 import static com.google.gerrit.json.OutputFormat.JSON;
 
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.model.OAuthRequest;
+import com.github.scribejava.core.model.Response;
+import com.github.scribejava.core.model.Verb;
+import com.github.scribejava.core.oauth.OAuth20Service;
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Strings;
@@ -38,15 +44,9 @@
 import java.nio.charset.StandardCharsets;
 import java.util.Arrays;
 import java.util.List;
+import java.util.concurrent.ExecutionException;
 import javax.servlet.http.HttpServletResponse;
 import org.apache.commons.codec.binary.Base64;
-import org.scribe.builder.ServiceBuilder;
-import org.scribe.model.OAuthRequest;
-import org.scribe.model.Response;
-import org.scribe.model.Token;
-import org.scribe.model.Verb;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -58,7 +58,7 @@
   private static final String PROTECTED_RESOURCE_URL =
       "https://www.googleapis.com/oauth2/v2/userinfo";
   private static final String SCOPE = "email profile";
-  private final OAuthService service;
+  private final OAuth20Service service;
   private final String canonicalWebUrl;
   private final List<String> domains;
   private final boolean useEmailAsUsername;
@@ -80,13 +80,11 @@
     this.domains = Arrays.asList(cfg.getStringList(InitOAuth.DOMAIN));
     this.useEmailAsUsername = cfg.getBoolean(InitOAuth.USE_EMAIL_AS_USERNAME, false);
     this.service =
-        new ServiceBuilder()
-            .provider(Google2Api.class)
-            .apiKey(cfg.getString(InitOAuth.CLIENT_ID))
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
             .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
             .callback(canonicalWebUrl + "oauth")
-            .scope(SCOPE)
-            .build();
+            .defaultScope(SCOPE)
+            .build(new Google2Api());
     if (log.isDebugEnabled()) {
       log.debug("OAuth2: canonicalWebUrl={}", canonicalWebUrl);
       log.debug("OAuth2: scope={}", SCOPE);
@@ -98,54 +96,59 @@
   @Override
   public OAuthUserInfo getUserInfo(OAuthToken token) throws IOException {
     OAuthRequest request = new OAuthRequest(Verb.GET, PROTECTED_RESOURCE_URL);
-    Token t = new Token(token.getToken(), token.getSecret(), token.getRaw());
+    OAuth2AccessToken t = new OAuth2AccessToken(token.getToken(), token.getRaw());
     service.signRequest(t, request);
-    Response response = request.send();
-    if (response.getCode() != HttpServletResponse.SC_OK) {
-      throw new IOException(
-          String.format(
-              "Status %s (%s) for request %s",
-              response.getCode(), response.getBody(), request.getUrl()));
-    }
-    JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
-    if (log.isDebugEnabled()) {
-      log.debug("User info response: {}", response.getBody());
-    }
-    if (userJson.isJsonObject()) {
-      JsonObject jsonObject = userJson.getAsJsonObject();
-      JsonElement id = jsonObject.get("id");
-      if (id == null || id.isJsonNull()) {
-        throw new IOException("Response doesn't contain id field");
-      }
-      JsonElement email = jsonObject.get("email");
-      JsonElement name = jsonObject.get("name");
-      String login = null;
 
-      if (domains.size() > 0) {
-        boolean domainMatched = false;
-        JsonObject jwtToken = retrieveJWTToken(token);
-        String hdClaim = retrieveHostedDomain(jwtToken);
-        for (String domain : domains) {
-          if (domain.equalsIgnoreCase(hdClaim)) {
-            domainMatched = true;
-            break;
+    JsonElement userJson = null;
+    try (Response response = service.execute(request)) {
+      if (response.getCode() != HttpServletResponse.SC_OK) {
+        throw new IOException(
+            String.format(
+                "Status %s (%s) for request %s",
+                response.getCode(), response.getBody(), request.getUrl()));
+      }
+      userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
+      if (log.isDebugEnabled()) {
+        log.debug("User info response: {}", response.getBody());
+      }
+      if (userJson.isJsonObject()) {
+        JsonObject jsonObject = userJson.getAsJsonObject();
+        JsonElement id = jsonObject.get("id");
+        if (id == null || id.isJsonNull()) {
+          throw new IOException("Response doesn't contain id field");
+        }
+        JsonElement email = jsonObject.get("email");
+        JsonElement name = jsonObject.get("name");
+        String login = null;
+
+        if (domains.size() > 0) {
+          boolean domainMatched = false;
+          JsonObject jwtToken = retrieveJWTToken(token);
+          String hdClaim = retrieveHostedDomain(jwtToken);
+          for (String domain : domains) {
+            if (domain.equalsIgnoreCase(hdClaim)) {
+              domainMatched = true;
+              break;
+            }
+          }
+          if (!domainMatched) {
+            // TODO(davido): improve error reporting in OAuth extension point
+            log.error("Error: hosted domain validation failed: {}", Strings.nullToEmpty(hdClaim));
+            return null;
           }
         }
-        if (!domainMatched) {
-          // TODO(davido): improve error reporting in OAuth extension point
-          log.error("Error: hosted domain validation failed: {}", Strings.nullToEmpty(hdClaim));
-          return null;
+        if (useEmailAsUsername && !email.isJsonNull()) {
+          login = email.getAsString().split("@")[0];
         }
+        return new OAuthUserInfo(
+            GOOGLE_PROVIDER_PREFIX + id.getAsString() /*externalId*/,
+            login /*username*/,
+            email == null || email.isJsonNull() ? null : email.getAsString() /*email*/,
+            name == null || name.isJsonNull() ? null : name.getAsString() /*displayName*/,
+            fixLegacyUserId ? id.getAsString() : null /*claimedIdentity*/);
       }
-      if (useEmailAsUsername && !email.isJsonNull()) {
-        login = email.getAsString().split("@")[0];
-      }
-      return new OAuthUserInfo(
-          GOOGLE_PROVIDER_PREFIX + id.getAsString() /*externalId*/,
-          login /*username*/,
-          email == null || email.isJsonNull() ? null : email.getAsString() /*email*/,
-          name == null || name.isJsonNull() ? null : name.getAsString() /*displayName*/,
-          fixLegacyUserId ? id.getAsString() : null /*claimedIdentity*/);
+    } catch (ExecutionException | InterruptedException e) {
+      throw new RuntimeException("Cannot retrieve user info resource", e);
     }
 
     throw new IOException(String.format("Invalid JSON '%s': not a JSON Object", userJson));
@@ -197,15 +200,20 @@
 
   @Override
   public OAuthToken getAccessToken(OAuthVerifier rv) {
-    Verifier vi = new Verifier(rv.getValue());
-    Token to = service.getAccessToken(null, vi);
-    OAuthToken result = new OAuthToken(to.getToken(), to.getSecret(), to.getRawResponse());
-    return result;
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
   }
 
   @Override
   public String getAuthorizationUrl() {
-    String url = service.getAuthorizationUrl(null);
+    String url = service.getAuthorizationUrl();
     try {
       if (domains.size() == 1) {
         url += "&hd=" + URLEncoder.encode(domains.get(0), StandardCharsets.UTF_8.name());
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/HttpModule.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/HttpModule.java
index e9e0b8f..c28f932 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/HttpModule.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/HttpModule.java
@@ -78,6 +78,13 @@
           .to(GitLabOAuthService.class);
     }
 
+    cfg = cfgFactory.getFromGerritConfig(pluginName + LemonLDAPOAuthService.CONFIG_SUFFIX);
+    if (cfg.getString(InitOAuth.CLIENT_ID) != null) {
+      bind(OAuthServiceProvider.class)
+          .annotatedWith(Exports.named(LemonLDAPOAuthService.CONFIG_SUFFIX))
+          .to(LemonLDAPOAuthService.class);
+    }
+
     cfg = cfgFactory.getFromGerritConfig(pluginName + DexOAuthService.CONFIG_SUFFIX);
     if (cfg.getString(InitOAuth.CLIENT_ID) != null) {
       bind(OAuthServiceProvider.class)
@@ -99,18 +106,11 @@
           .to(Office365OAuthService.class);
     }
 
-    cfg = cfgFactory.getFromGerritConfig(pluginName + WarsawHackerspaceOAuthService.CONFIG_SUFFIX);
+    cfg = cfgFactory.getFromGerritConfig(pluginName + AirVantageOAuthService.CONFIG_SUFFIX);
     if (cfg.getString(InitOAuth.CLIENT_ID) != null) {
       bind(OAuthServiceProvider.class)
-          .annotatedWith(Exports.named(WarsawHackerspaceOAuthService.CONFIG_SUFFIX))
-          .to(WarsawHackerspaceOAuthService.class);
-    }
-
-    cfg = cfgFactory.getFromGerritConfig(pluginName + WarsawHackerspaceOAuthService.CONFIG_SUFFIX);
-    if (cfg.getString(InitOAuth.CLIENT_ID) != null) {
-      bind(OAuthServiceProvider.class)
-          .annotatedWith(Exports.named(WarsawHackerspaceOAuthService.CONFIG_SUFFIX))
-          .to(WarsawHackerspaceOAuthService.class);
+          .annotatedWith(Exports.named(AirVantageOAuthService.CONFIG_SUFFIX))
+          .to(AirVantageOAuthService.class);
     }
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/InitOAuth.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/InitOAuth.java
index 50c0590..0da32ce 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/InitOAuth.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/InitOAuth.java
@@ -13,11 +13,16 @@
 // limitations under the License.
 package com.googlesource.gerrit.plugins.oauth;
 
+import static java.util.Objects.requireNonNull;
+
+import com.google.common.base.Strings;
 import com.google.gerrit.extensions.annotations.PluginName;
 import com.google.gerrit.pgm.init.api.ConsoleUI;
 import com.google.gerrit.pgm.init.api.InitStep;
 import com.google.gerrit.pgm.init.api.Section;
 import com.google.inject.Inject;
+import com.google.inject.ProvisionException;
+import java.net.URI;
 
 class InitOAuth implements InitStep {
   static final String PLUGIN_SECTION = "plugin";
@@ -39,11 +44,11 @@
   private final Section casOAuthProviderSection;
   private final Section facebookOAuthProviderSection;
   private final Section gitlabOAuthProviderSection;
+  private final Section lemonldapOAuthProviderSection;
   private final Section dexOAuthProviderSection;
   private final Section keycloakOAuthProviderSection;
   private final Section office365OAuthProviderSection;
   private final Section airVantageOAuthProviderSection;
-  private final Section warsawHackerspaceOAuthProviderSection;
 
   @Inject
   InitOAuth(ConsoleUI ui, Section.Factory sections, @PluginName String pluginName) {
@@ -60,6 +65,8 @@
         sections.get(PLUGIN_SECTION, pluginName + FacebookOAuthService.CONFIG_SUFFIX);
     this.gitlabOAuthProviderSection =
         sections.get(PLUGIN_SECTION, pluginName + GitLabOAuthService.CONFIG_SUFFIX);
+    this.lemonldapOAuthProviderSection =
+        sections.get(PLUGIN_SECTION, pluginName + LemonLDAPOAuthService.CONFIG_SUFFIX);
     this.dexOAuthProviderSection =
         sections.get(PLUGIN_SECTION, pluginName + DexOAuthService.CONFIG_SUFFIX);
     this.keycloakOAuthProviderSection =
@@ -68,8 +75,6 @@
         sections.get(PLUGIN_SECTION, pluginName + Office365OAuthService.CONFIG_SUFFIX);
     this.airVantageOAuthProviderSection =
         sections.get(PLUGIN_SECTION, pluginName + AirVantageOAuthService.CONFIG_SUFFIX);
-    this.warsawHackerspaceOAuthProviderSection = 
-        sections.get(PLUGIN_SECTION, pluginName + WarsawHackerspaceOAuthService.CONFIG_SUFFIX);
   }
 
   @Override
@@ -77,83 +82,129 @@
     ui.header("OAuth Authentication Provider");
 
     boolean configureGoogleOAuthProvider =
-        ui.yesno(true, "Use Google OAuth provider for Gerrit login ?");
-    if (configureGoogleOAuthProvider) {
-      configureOAuth(googleOAuthProviderSection);
+        ui.yesno(
+            isConfigured(googleOAuthProviderSection),
+            "Use Google OAuth provider for Gerrit login ?");
+    if (configureGoogleOAuthProvider && configureOAuth(googleOAuthProviderSection)) {
       googleOAuthProviderSection.string(FIX_LEGACY_USER_ID_QUESTION, FIX_LEGACY_USER_ID, "false");
     }
 
     boolean configueGitHubOAuthProvider =
-        ui.yesno(true, "Use GitHub OAuth provider for Gerrit login ?");
-    if (configueGitHubOAuthProvider) {
-      configureOAuth(githubOAuthProviderSection);
+        ui.yesno(
+            isConfigured(githubOAuthProviderSection),
+            "Use GitHub OAuth provider for Gerrit login ?");
+    if (configueGitHubOAuthProvider && configureOAuth(githubOAuthProviderSection)) {
       githubOAuthProviderSection.string(FIX_LEGACY_USER_ID_QUESTION, FIX_LEGACY_USER_ID, "false");
     }
 
     boolean configureBitbucketOAuthProvider =
-        ui.yesno(true, "Use Bitbucket OAuth provider for Gerrit login ?");
-    if (configureBitbucketOAuthProvider) {
-      configureOAuth(bitbucketOAuthProviderSection);
+        ui.yesno(
+            isConfigured(bitbucketOAuthProviderSection),
+            "Use Bitbucket OAuth provider for Gerrit login ?");
+    if (configureBitbucketOAuthProvider && configureOAuth(bitbucketOAuthProviderSection)) {
       bitbucketOAuthProviderSection.string(
           FIX_LEGACY_USER_ID_QUESTION, FIX_LEGACY_USER_ID, "false");
     }
 
-    boolean configureCasOAuthProvider = ui.yesno(true, "Use CAS OAuth provider for Gerrit login ?");
-    if (configureCasOAuthProvider) {
-      casOAuthProviderSection.string("CAS Root URL", ROOT_URL, null);
-      configureOAuth(casOAuthProviderSection);
+    boolean configureCasOAuthProvider =
+        ui.yesno(
+            isConfigured(casOAuthProviderSection), "Use CAS OAuth provider for Gerrit login ?");
+    if (configureCasOAuthProvider && configureOAuth(casOAuthProviderSection)) {
+      checkRootUrl(casOAuthProviderSection.string("CAS Root URL", ROOT_URL, null));
       casOAuthProviderSection.string(FIX_LEGACY_USER_ID_QUESTION, FIX_LEGACY_USER_ID, "false");
     }
 
     boolean configueFacebookOAuthProvider =
-        ui.yesno(true, "Use Facebook OAuth provider for Gerrit login ?");
+        ui.yesno(
+            isConfigured(facebookOAuthProviderSection),
+            "Use Facebook OAuth provider for Gerrit login ?");
     if (configueFacebookOAuthProvider) {
       configureOAuth(facebookOAuthProviderSection);
     }
 
     boolean configureGitLabOAuthProvider =
-        ui.yesno(true, "Use GitLab OAuth provider for Gerrit login ?");
-    if (configureGitLabOAuthProvider) {
-      gitlabOAuthProviderSection.string("GitLab Root URL", ROOT_URL, null);
-      configureOAuth(gitlabOAuthProviderSection);
+        ui.yesno(
+            isConfigured(gitlabOAuthProviderSection),
+            "Use GitLab OAuth provider for Gerrit login ?");
+    if (configureGitLabOAuthProvider && configureOAuth(gitlabOAuthProviderSection)) {
+      checkRootUrl(gitlabOAuthProviderSection.string("GitLab Root URL", ROOT_URL, null));
     }
 
-    boolean configureDexOAuthProvider = ui.yesno(true, "Use Dex OAuth provider for Gerrit login ?");
-    if (configureDexOAuthProvider) {
-      dexOAuthProviderSection.string("Dex Root URL", ROOT_URL, null);
-      configureOAuth(dexOAuthProviderSection);
+    boolean configureLemonLDAPOAuthProvider =
+        ui.yesno(true, "Use LemonLDAP OAuth provider for Gerrit login ?");
+    if (configureLemonLDAPOAuthProvider) {
+      checkRootUrl(lemonldapOAuthProviderSection.string("LemonLDAP Root URL", ROOT_URL, null));
+      configureOAuth(lemonldapOAuthProviderSection);
+    }
+
+    boolean configureDexOAuthProvider =
+        ui.yesno(
+            isConfigured(dexOAuthProviderSection), "Use Dex OAuth provider for Gerrit login ?");
+    if (configureDexOAuthProvider && configureOAuth(dexOAuthProviderSection)) {
+      checkRootUrl(dexOAuthProviderSection.string("Dex Root URL", ROOT_URL, null));
     }
 
     boolean configureKeycloakOAuthProvider =
-        ui.yesno(true, "Use Keycloak OAuth provider for Gerrit login ?");
-    if (configureKeycloakOAuthProvider) {
-      keycloakOAuthProviderSection.string("Keycloak Root URL", ROOT_URL, null);
+        ui.yesno(
+            isConfigured(keycloakOAuthProviderSection),
+            "Use Keycloak OAuth provider for Gerrit login ?");
+    if (configureKeycloakOAuthProvider && configureOAuth(keycloakOAuthProviderSection)) {
+      checkRootUrl(keycloakOAuthProviderSection.string("Keycloak Root URL", ROOT_URL, null));
       keycloakOAuthProviderSection.string("Keycloak Realm", REALM, null);
-      configureOAuth(keycloakOAuthProviderSection);
     }
 
     boolean configureOffice365OAuthProvider =
-        ui.yesno(true, "Use Office365 OAuth provider for Gerrit login ?");
+        ui.yesno(
+            isConfigured(office365OAuthProviderSection),
+            "Use Office365 OAuth provider for Gerrit login ?");
     if (configureOffice365OAuthProvider) {
       configureOAuth(office365OAuthProviderSection);
     }
 
     boolean configureAirVantageOAuthProvider =
-        ui.yesno(true, "Use AirVantage OAuth provider for Gerrit login ?");
+        ui.yesno(
+            isConfigured(airVantageOAuthProviderSection),
+            "Use AirVantage OAuth provider for Gerrit login ?");
     if (configureAirVantageOAuthProvider) {
       configureOAuth(airVantageOAuthProviderSection);
     }
-
-    boolean configureWarsawHackerspaceOAuthProvider = 
-        ui.yesno(true, "Use Warsaw Hackerspace OAuth provider for Gerrit login?");
-    if (configureWarsawHackerspaceOAuthProvider) {
-      configureOAuth(warsawHackerspaceOAuthProviderSection);
-    }
   }
 
-  private void configureOAuth(Section s) {
-    s.string("Application client id", CLIENT_ID, null);
-    s.passwordForKey("Application client secret", CLIENT_SECRET);
+  /**
+   * Retrieve client id to check whether or not this provider was already configured.
+   *
+   * @param s OAuth provider section
+   * @return true if client id key is present, false otherwise
+   */
+  private static boolean isConfigured(Section s) {
+    return !Strings.isNullOrEmpty(s.get(CLIENT_ID));
+  }
+
+  /**
+   * Configure OAuth provider section
+   *
+   * @param s section to configure
+   * @return true if section is present, false otherwise
+   */
+  private static boolean configureOAuth(Section s) {
+    if (!Strings.isNullOrEmpty(s.string("Application client id", CLIENT_ID, null))) {
+      s.passwordForKey("Application client secret", CLIENT_SECRET);
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Check root URL parameter. It must be not null and it must be an absolute URI.
+   *
+   * @param rootUrl root URL
+   * @throws ProvisionException if rootUrl wasn't provided or is not absolute URI.
+   */
+  private static void checkRootUrl(String rootUrl) {
+    requireNonNull(rootUrl);
+    if (!URI.create(rootUrl).isAbsolute()) {
+      throw new ProvisionException("Root URL must be absolute URL");
+    }
   }
 
   @Override
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/KeycloakApi.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/KeycloakApi.java
index 581d562..21e0749 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/KeycloakApi.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/KeycloakApi.java
@@ -14,18 +14,15 @@
 
 package com.googlesource.gerrit.plugins.oauth;
 
-import org.scribe.builder.api.DefaultApi20;
-import org.scribe.extractors.AccessTokenExtractor;
-import org.scribe.extractors.JsonTokenExtractor;
-import org.scribe.model.OAuthConfig;
-import org.scribe.model.Verb;
-import org.scribe.oauth.OAuthService;
-import org.scribe.utils.OAuthEncoder;
+import com.github.scribejava.core.builder.api.DefaultApi20;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignature;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignatureURIQueryParameter;
+import com.github.scribejava.core.oauth2.clientauthentication.ClientAuthentication;
+import com.github.scribejava.core.oauth2.clientauthentication.RequestBodyAuthenticationScheme;
 
 public class KeycloakApi extends DefaultApi20 {
 
-  private static final String AUTHORIZE_URL =
-      "%s/auth/realms/%s/protocol/openid-connect/auth?client_id=%s&response_type=code&redirect_uri=%s&scope=%s";
+  private static final String AUTHORIZE_URL = "%s/auth/realms/%s/protocol/openid-connect/auth";
 
   private final String rootUrl;
   private final String realm;
@@ -36,14 +33,8 @@
   }
 
   @Override
-  public String getAuthorizationUrl(OAuthConfig config) {
-    return String.format(
-        AUTHORIZE_URL,
-        rootUrl,
-        realm,
-        config.getApiKey(),
-        OAuthEncoder.encode(config.getCallback()),
-        config.getScope().replaceAll(" ", "+"));
+  public String getAuthorizationBaseUrl() {
+    return String.format(AUTHORIZE_URL, rootUrl, realm);
   }
 
   @Override
@@ -52,17 +43,12 @@
   }
 
   @Override
-  public Verb getAccessTokenVerb() {
-    return Verb.POST;
+  public BearerSignature getBearerSignature() {
+    return BearerSignatureURIQueryParameter.instance();
   }
 
   @Override
-  public OAuthService createService(OAuthConfig config) {
-    return new OAuth20ServiceImpl(this, config);
-  }
-
-  @Override
-  public AccessTokenExtractor getAccessTokenExtractor() {
-    return new JsonTokenExtractor();
+  public ClientAuthentication getClientAuthentication() {
+    return RequestBodyAuthenticationScheme.instance();
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/KeycloakOAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/KeycloakOAuthService.java
index b6a0cdf..34f3f87 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/KeycloakOAuthService.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/KeycloakOAuthService.java
@@ -16,6 +16,9 @@
 
 import static com.google.gerrit.json.OutputFormat.JSON;
 
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.oauth.OAuth20Service;
 import com.google.common.base.CharMatcher;
 import com.google.common.base.Preconditions;
 import com.google.gerrit.extensions.annotations.PluginName;
@@ -30,12 +33,11 @@
 import com.google.gson.JsonObject;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
+import com.google.inject.ProvisionException;
 import java.io.IOException;
+import java.net.URI;
+import java.util.concurrent.ExecutionException;
 import org.apache.commons.codec.binary.Base64;
-import org.scribe.builder.ServiceBuilder;
-import org.scribe.model.Token;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -45,7 +47,7 @@
 
   static final String CONFIG_SUFFIX = "-keycloak-oauth";
   private static final String KEYCLOAK_PROVIDER_PREFIX = "keycloak-oauth:";
-  private final OAuthService service;
+  private final OAuth20Service service;
   private final String serviceName;
 
   @Inject
@@ -57,17 +59,18 @@
     String canonicalWebUrl = CharMatcher.is('/').trimTrailingFrom(urlProvider.get()) + "/";
 
     String rootUrl = cfg.getString(InitOAuth.ROOT_URL);
+    if (!URI.create(rootUrl).isAbsolute()) {
+      throw new ProvisionException("Root URL must be absolute URL");
+    }
     String realm = cfg.getString(InitOAuth.REALM);
     serviceName = cfg.getString(InitOAuth.SERVICE_NAME, "Keycloak OAuth2");
 
     service =
-        new ServiceBuilder()
-            .provider(new KeycloakApi(rootUrl, realm))
-            .apiKey(cfg.getString(InitOAuth.CLIENT_ID))
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
             .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
-            .scope("openid")
             .callback(canonicalWebUrl + "oauth")
-            .build();
+            .defaultScope("openid")
+            .build(new KeycloakApi(rootUrl, realm));
   }
 
   private String parseJwt(String input) {
@@ -116,14 +119,20 @@
 
   @Override
   public OAuthToken getAccessToken(OAuthVerifier rv) {
-    Verifier vi = new Verifier(rv.getValue());
-    Token to = service.getAccessToken(null, vi);
-    return new OAuthToken(to.getToken(), to.getSecret(), to.getRawResponse());
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
   }
 
   @Override
   public String getAuthorizationUrl() {
-    return service.getAuthorizationUrl(null);
+    return service.getAuthorizationUrl();
   }
 
   @Override
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/LemonLDAPApi.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/LemonLDAPApi.java
new file mode 100644
index 0000000..7b66c25
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/LemonLDAPApi.java
@@ -0,0 +1,55 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import com.github.scribejava.core.builder.api.DefaultApi20;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignature;
+import com.github.scribejava.core.oauth2.bearersignature.BearerSignatureURIQueryParameter;
+import com.github.scribejava.core.oauth2.clientauthentication.ClientAuthentication;
+import com.github.scribejava.core.oauth2.clientauthentication.RequestBodyAuthenticationScheme;
+
+public class LemonLDAPApi extends DefaultApi20 {
+  private static final String AUTHORIZE_URL = "%s/oauth2/authorize";
+
+  private final String rootUrl;
+
+  public LemonLDAPApi(String rootUrl) {
+    this.rootUrl = rootUrl;
+  }
+
+  @Override
+  public String getAuthorizationBaseUrl() {
+    return String.format(AUTHORIZE_URL, rootUrl);
+  }
+
+  @Override
+  public String getAccessTokenEndpoint() {
+    return String.format("%s/oauth2/token", rootUrl);
+  }
+
+  // TODO(davido): Remove this override, if HttpBasicAuthentication
+  // scheme is supported.
+  @Override
+  public ClientAuthentication getClientAuthentication() {
+    return RequestBodyAuthenticationScheme.instance();
+  }
+
+  // TODO(davido): Remove this override, if BearerSignatureAuthorization
+  // request header field is supported.
+  @Override
+  public BearerSignature getBearerSignature() {
+    return BearerSignatureURIQueryParameter.instance();
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/LemonLDAPOAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/LemonLDAPOAuthService.java
new file mode 100644
index 0000000..f1a0dbe
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/LemonLDAPOAuthService.java
@@ -0,0 +1,134 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.gerrit.json.OutputFormat.JSON;
+import static org.slf4j.LoggerFactory.getLogger;
+
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.model.OAuthRequest;
+import com.github.scribejava.core.model.Response;
+import com.github.scribejava.core.model.Verb;
+import com.github.scribejava.core.oauth.OAuth20Service;
+import com.google.common.base.CharMatcher;
+import com.google.gerrit.extensions.annotations.PluginName;
+import com.google.gerrit.extensions.auth.oauth.OAuthServiceProvider;
+import com.google.gerrit.extensions.auth.oauth.OAuthToken;
+import com.google.gerrit.extensions.auth.oauth.OAuthUserInfo;
+import com.google.gerrit.extensions.auth.oauth.OAuthVerifier;
+import com.google.gerrit.server.config.CanonicalWebUrl;
+import com.google.gerrit.server.config.PluginConfig;
+import com.google.gerrit.server.config.PluginConfigFactory;
+import com.google.gson.JsonElement;
+import com.google.gson.JsonObject;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+import com.google.inject.Singleton;
+import java.io.IOException;
+import java.util.concurrent.ExecutionException;
+import javax.servlet.http.HttpServletResponse;
+import org.slf4j.Logger;
+
+@Singleton
+public class LemonLDAPOAuthService implements OAuthServiceProvider {
+  private static final Logger log = getLogger(LemonLDAPOAuthService.class);
+  static final String CONFIG_SUFFIX = "-lemonldap-oauth";
+  private static final String PROTECTED_RESOURCE_URL = "%s/oauth2/userinfo";
+  private static final String LEMONLDAP_PROVIDER_PREFIX = "llng-oauth:";
+  private final OAuth20Service service;
+  private final String rootUrl;
+
+  @Inject
+  LemonLDAPOAuthService(
+      PluginConfigFactory cfgFactory,
+      @PluginName String pluginName,
+      @CanonicalWebUrl Provider<String> urlProvider) {
+    PluginConfig cfg = cfgFactory.getFromGerritConfig(pluginName + CONFIG_SUFFIX);
+    String canonicalWebUrl = CharMatcher.is('/').trimTrailingFrom(urlProvider.get()) + "/";
+    rootUrl = cfg.getString(InitOAuth.ROOT_URL);
+    service =
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
+            .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
+            .defaultScope("openid+email+profile")
+            .callback(canonicalWebUrl + "oauth")
+            .build(new LemonLDAPApi(rootUrl));
+  }
+
+  @Override
+  public OAuthUserInfo getUserInfo(OAuthToken token) throws IOException {
+    OAuthRequest request =
+        new OAuthRequest(Verb.GET, String.format(PROTECTED_RESOURCE_URL, rootUrl));
+    OAuth2AccessToken t = new OAuth2AccessToken(token.getToken(), token.getRaw());
+    service.signRequest(t, request);
+
+    try (Response response = service.execute(request)) {
+      if (response.getCode() != HttpServletResponse.SC_OK) {
+        throw new IOException(
+            String.format(
+                "Status %s (%s) for request %s",
+                response.getCode(), response.getBody(), request.getUrl()));
+      }
+      JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
+      if (log.isDebugEnabled()) {
+        log.debug("User info response: {}", response.getBody());
+      }
+      JsonObject jsonObject = userJson.getAsJsonObject();
+      if (jsonObject == null || jsonObject.isJsonNull()) {
+        throw new IOException("Response doesn't contain 'user' field" + jsonObject);
+      }
+      JsonElement id = jsonObject.get("sub");
+      JsonElement username = jsonObject.get("username");
+      JsonElement email = jsonObject.get("email");
+      JsonElement name = jsonObject.get("name");
+      return new OAuthUserInfo(
+          LEMONLDAP_PROVIDER_PREFIX + id.getAsString(),
+          username == null || username.isJsonNull() ? null : username.getAsString(),
+          email == null || email.isJsonNull() ? null : email.getAsString(),
+          name == null || name.isJsonNull() ? null : name.getAsString(),
+          null);
+    } catch (ExecutionException | InterruptedException e) {
+      throw new RuntimeException("Cannot retrieve user info resource", e);
+    }
+  }
+
+  @Override
+  public OAuthToken getAccessToken(OAuthVerifier rv) {
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
+  }
+
+  @Override
+  public String getAuthorizationUrl() {
+    return service.getAuthorizationUrl();
+  }
+
+  @Override
+  public String getVersion() {
+    return service.getVersion();
+  }
+
+  @Override
+  public String getName() {
+    return "LemonLDAP::NG OAuth2 provider";
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/OAuth20ServiceImpl.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/OAuth20ServiceImpl.java
deleted file mode 100644
index ecd8f26..0000000
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/OAuth20ServiceImpl.java
+++ /dev/null
@@ -1,93 +0,0 @@
-// Copyright (C) 2017 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.googlesource.gerrit.plugins.oauth;
-
-import static org.slf4j.LoggerFactory.getLogger;
-
-import org.scribe.builder.api.DefaultApi20;
-import org.scribe.model.OAuthConfig;
-import org.scribe.model.OAuthConstants;
-import org.scribe.model.OAuthRequest;
-import org.scribe.model.Response;
-import org.scribe.model.Token;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
-import org.slf4j.Logger;
-
-/** TODO(gildur): remove when updating to newer scribe lib */
-final class OAuth20ServiceImpl implements OAuthService {
-  private static final Logger log = getLogger(OAuth20ServiceImpl.class);
-
-  private static final String VERSION = "2.0";
-
-  private static final String GRANT_TYPE = "grant_type";
-  private static final String GRANT_TYPE_VALUE = "authorization_code";
-
-  private final DefaultApi20 api;
-  private final OAuthConfig config;
-
-  /**
-   * Default constructor
-   *
-   * @param api OAuth2.0 api information
-   * @param config OAuth 2.0 configuration param object
-   */
-  public OAuth20ServiceImpl(DefaultApi20 api, OAuthConfig config) {
-    this.api = api;
-    this.config = config;
-  }
-
-  @Override
-  public Token getAccessToken(Token requestToken, Verifier verifier) {
-    OAuthRequest request = new OAuthRequest(api.getAccessTokenVerb(), api.getAccessTokenEndpoint());
-    request.addBodyParameter(OAuthConstants.CLIENT_ID, config.getApiKey());
-    request.addBodyParameter(OAuthConstants.CLIENT_SECRET, config.getApiSecret());
-    request.addBodyParameter(OAuthConstants.CODE, verifier.getValue());
-    request.addBodyParameter(OAuthConstants.REDIRECT_URI, config.getCallback());
-    if (config.hasScope()) {
-      request.addBodyParameter(OAuthConstants.SCOPE, config.getScope());
-    }
-    request.addBodyParameter(GRANT_TYPE, GRANT_TYPE_VALUE);
-    if (log.isDebugEnabled()) {
-      log.debug("Access token request: {}", request);
-    }
-    Response response = request.send();
-    if (log.isDebugEnabled()) {
-      log.debug("Access token response: {}", response.getBody());
-    }
-    return api.getAccessTokenExtractor().extract(response.getBody());
-  }
-
-  @Override
-  public Token getRequestToken() {
-    throw new UnsupportedOperationException(
-        "Unsupported operation, please use 'getAuthorizationUrl' and redirect your users there");
-  }
-
-  @Override
-  public String getVersion() {
-    return VERSION;
-  }
-
-  @Override
-  public void signRequest(Token accessToken, OAuthRequest request) {
-    request.addQuerystringParameter(OAuthConstants.ACCESS_TOKEN, accessToken.getToken());
-  }
-
-  @Override
-  public String getAuthorizationUrl(Token requestToken) {
-    return api.getAuthorizationUrl(config);
-  }
-}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/OAuth2AccessTokenJsonExtractor.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/OAuth2AccessTokenJsonExtractor.java
deleted file mode 100644
index 6c2f1a0..0000000
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/OAuth2AccessTokenJsonExtractor.java
+++ /dev/null
@@ -1,49 +0,0 @@
-// Copyright (C) 2018 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.googlesource.gerrit.plugins.oauth;
-
-import static org.scribe.model.OAuthConstants.ACCESS_TOKEN;
-
-import com.google.common.annotations.VisibleForTesting;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-import org.scribe.exceptions.OAuthException;
-import org.scribe.extractors.AccessTokenExtractor;
-import org.scribe.model.Token;
-import org.scribe.utils.Preconditions;
-
-class OAuth2AccessTokenJsonExtractor implements AccessTokenExtractor {
-  private static final Pattern ACCESS_TOKEN_REGEX_PATTERN =
-      Pattern.compile("\"" + ACCESS_TOKEN + "\"\\s*:\\s*\"(\\S*?)\"");
-
-  private OAuth2AccessTokenJsonExtractor() {}
-
-  private static final AccessTokenExtractor INSTANCE = new OAuth2AccessTokenJsonExtractor();
-
-  static AccessTokenExtractor instance() {
-    return INSTANCE;
-  }
-
-  @VisibleForTesting
-  @Override
-  public Token extract(String response) {
-    Preconditions.checkEmptyString(response, "Cannot extract a token from a null or empty String");
-    Matcher matcher = ACCESS_TOKEN_REGEX_PATTERN.matcher(response);
-    if (matcher.find()) {
-      return new Token(matcher.group(1), "", response);
-    }
-    throw new OAuthException("Cannot extract an access token. Response was: " + response);
-  }
-}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365Api.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365Api.java
index 8a28520..7e9bef8 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365Api.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365Api.java
@@ -14,49 +14,23 @@
 
 package com.googlesource.gerrit.plugins.oauth;
 
-import static org.scribe.utils.OAuthEncoder.encode;
-
-import org.scribe.builder.api.DefaultApi20;
-import org.scribe.extractors.AccessTokenExtractor;
-import org.scribe.model.OAuthConfig;
-import org.scribe.model.Verb;
-import org.scribe.oauth.OAuthService;
-import org.scribe.utils.Preconditions;
+import com.github.scribejava.core.builder.api.DefaultApi20;
+import com.github.scribejava.core.oauth2.clientauthentication.ClientAuthentication;
+import com.github.scribejava.core.oauth2.clientauthentication.RequestBodyAuthenticationScheme;
 
 public class Office365Api extends DefaultApi20 {
-  private static final String AUTHORIZE_URL =
-      "https://login.microsoftonline.com/organizations/oauth2/v2.0/authorize?client_id=%s&response_type=code&redirect_uri=%s&scope=%s";
-
   @Override
   public String getAccessTokenEndpoint() {
     return "https://login.microsoftonline.com/organizations/oauth2/v2.0/token";
   }
 
   @Override
-  public String getAuthorizationUrl(OAuthConfig config) {
-    Preconditions.checkValidUrl(
-        config.getCallback(),
-        "Must provide a valid url as callback. Office365 does not support OOB");
-    Preconditions.checkEmptyString(
-        config.getScope(),
-        "Must provide a valid value as scope. Office365 does not support no scope");
-
-    return String.format(
-        AUTHORIZE_URL, config.getApiKey(), encode(config.getCallback()), encode(config.getScope()));
+  public String getAuthorizationBaseUrl() {
+    return "https://login.microsoftonline.com/organizations/oauth2/v2.0/authorize";
   }
 
   @Override
-  public Verb getAccessTokenVerb() {
-    return Verb.POST;
-  }
-
-  @Override
-  public OAuthService createService(OAuthConfig config) {
-    return new OAuth20ServiceImpl(this, config);
-  }
-
-  @Override
-  public AccessTokenExtractor getAccessTokenExtractor() {
-    return OAuth2AccessTokenJsonExtractor.instance();
+  public ClientAuthentication getClientAuthentication() {
+    return RequestBodyAuthenticationScheme.instance();
   }
 }
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365OAuthService.java b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365OAuthService.java
index aee8f63..c1380bc 100644
--- a/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365OAuthService.java
+++ b/devtools/gerrit/gerrit-oauth-provider/src/main/java/com/googlesource/gerrit/plugins/oauth/Office365OAuthService.java
@@ -16,6 +16,12 @@
 
 import static com.google.gerrit.json.OutputFormat.JSON;
 
+import com.github.scribejava.core.builder.ServiceBuilder;
+import com.github.scribejava.core.model.OAuth2AccessToken;
+import com.github.scribejava.core.model.OAuthRequest;
+import com.github.scribejava.core.model.Response;
+import com.github.scribejava.core.model.Verb;
+import com.github.scribejava.core.oauth.OAuth20Service;
 import com.google.common.base.CharMatcher;
 import com.google.gerrit.extensions.annotations.PluginName;
 import com.google.gerrit.extensions.auth.oauth.OAuthServiceProvider;
@@ -31,14 +37,8 @@
 import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import java.io.IOException;
+import java.util.concurrent.ExecutionException;
 import javax.servlet.http.HttpServletResponse;
-import org.scribe.builder.ServiceBuilder;
-import org.scribe.model.OAuthRequest;
-import org.scribe.model.Response;
-import org.scribe.model.Token;
-import org.scribe.model.Verb;
-import org.scribe.model.Verifier;
-import org.scribe.oauth.OAuthService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -50,7 +50,7 @@
   private static final String PROTECTED_RESOURCE_URL = "https://graph.microsoft.com/v1.0/me";
   private static final String SCOPE =
       "openid offline_access https://graph.microsoft.com/user.readbasic.all";
-  private final OAuthService service;
+  private final OAuth20Service service;
   private final String canonicalWebUrl;
   private final boolean useEmailAsUsername;
 
@@ -63,13 +63,11 @@
     this.canonicalWebUrl = CharMatcher.is('/').trimTrailingFrom(urlProvider.get()) + "/";
     this.useEmailAsUsername = cfg.getBoolean(InitOAuth.USE_EMAIL_AS_USERNAME, false);
     this.service =
-        new ServiceBuilder()
-            .provider(Office365Api.class)
-            .apiKey(cfg.getString(InitOAuth.CLIENT_ID))
+        new ServiceBuilder(cfg.getString(InitOAuth.CLIENT_ID))
             .apiSecret(cfg.getString(InitOAuth.CLIENT_SECRET))
             .callback(canonicalWebUrl + "oauth")
-            .scope(SCOPE)
-            .build();
+            .defaultScope(SCOPE)
+            .build(new Office365Api());
     if (log.isDebugEnabled()) {
       log.debug("OAuth2: canonicalWebUrl={}", canonicalWebUrl);
       log.debug("OAuth2: scope={}", SCOPE);
@@ -80,38 +78,43 @@
   @Override
   public OAuthUserInfo getUserInfo(OAuthToken token) throws IOException {
     OAuthRequest request = new OAuthRequest(Verb.GET, PROTECTED_RESOURCE_URL);
-    request.addHeader("Accept", "*/*");
-    request.addHeader("Authorization", "Bearer " + token.getToken());
-    Response response = request.send();
-    if (response.getCode() != HttpServletResponse.SC_OK) {
-      throw new IOException(
-          String.format(
-              "Status %s (%s) for request %s",
-              response.getCode(), response.getBody(), request.getUrl()));
-    }
-    JsonElement userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
-    if (log.isDebugEnabled()) {
-      log.debug("User info response: {}", response.getBody());
-    }
-    if (userJson.isJsonObject()) {
-      JsonObject jsonObject = userJson.getAsJsonObject();
-      JsonElement id = jsonObject.get("id");
-      if (id == null || id.isJsonNull()) {
-        throw new IOException("Response doesn't contain id field");
-      }
-      JsonElement email = jsonObject.get("mail");
-      JsonElement name = jsonObject.get("displayName");
-      String login = null;
+    OAuth2AccessToken t = new OAuth2AccessToken(token.getToken(), token.getRaw());
+    service.signRequest(t, request);
 
-      if (useEmailAsUsername && !email.isJsonNull()) {
-        login = email.getAsString().split("@")[0];
+    JsonElement userJson = null;
+    try (Response response = service.execute(request)) {
+      if (response.getCode() != HttpServletResponse.SC_OK) {
+        throw new IOException(
+            String.format(
+                "Status %s (%s) for request %s",
+                response.getCode(), response.getBody(), request.getUrl()));
       }
-      return new OAuthUserInfo(
-          OFFICE365_PROVIDER_PREFIX + id.getAsString() /*externalId*/,
-          login /*username*/,
-          email == null || email.isJsonNull() ? null : email.getAsString() /*email*/,
-          name == null || name.isJsonNull() ? null : name.getAsString() /*displayName*/,
-          null);
+      userJson = JSON.newGson().fromJson(response.getBody(), JsonElement.class);
+      if (log.isDebugEnabled()) {
+        log.debug("User info response: {}", response.getBody());
+      }
+      if (userJson.isJsonObject()) {
+        JsonObject jsonObject = userJson.getAsJsonObject();
+        JsonElement id = jsonObject.get("id");
+        if (id == null || id.isJsonNull()) {
+          throw new IOException("Response doesn't contain id field");
+        }
+        JsonElement email = jsonObject.get("mail");
+        JsonElement name = jsonObject.get("displayName");
+        String login = null;
+
+        if (useEmailAsUsername && !email.isJsonNull()) {
+          login = email.getAsString().split("@")[0];
+        }
+        return new OAuthUserInfo(
+            OFFICE365_PROVIDER_PREFIX + id.getAsString() /*externalId*/,
+            login /*username*/,
+            email == null || email.isJsonNull() ? null : email.getAsString() /*email*/,
+            name == null || name.isJsonNull() ? null : name.getAsString() /*displayName*/,
+            null);
+      }
+    } catch (ExecutionException | InterruptedException e) {
+      throw new RuntimeException("Cannot retrieve user info resource", e);
     }
 
     throw new IOException(String.format("Invalid JSON '%s': not a JSON Object", userJson));
@@ -119,15 +122,20 @@
 
   @Override
   public OAuthToken getAccessToken(OAuthVerifier rv) {
-    Verifier vi = new Verifier(rv.getValue());
-    Token to = service.getAccessToken(null, vi);
-    OAuthToken result = new OAuthToken(to.getToken(), to.getSecret(), to.getRawResponse());
-    return result;
+    try {
+      OAuth2AccessToken accessToken = service.getAccessToken(rv.getValue());
+      return new OAuthToken(
+          accessToken.getAccessToken(), accessToken.getTokenType(), accessToken.getRawResponse());
+    } catch (InterruptedException | ExecutionException | IOException e) {
+      String msg = "Cannot retrieve access token";
+      log.error(msg, e);
+      throw new RuntimeException(msg, e);
+    }
   }
 
   @Override
   public String getAuthorizationUrl() {
-    String url = service.getAuthorizationUrl(null);
+    String url = service.getAuthorizationUrl();
     return url;
   }
 
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/AirVantageApiTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/AirVantageApiTest.java
new file mode 100644
index 0000000..9f2f3b3
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/AirVantageApiTest.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.github.scribejava.core.extractors.OAuth2AccessTokenJsonExtractor;
+import org.junit.Before;
+import org.junit.Test;
+
+public class AirVantageApiTest {
+  private AirVantageApi api;
+
+  @Before
+  public void setUp() {
+    api = new AirVantageApi();
+  }
+
+  @Test
+  public void testAccessTokenExtractor() {
+    assertThat(api.getAccessTokenExtractor()).isInstanceOf(OAuth2AccessTokenJsonExtractor.class);
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/BitbucketApiTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/BitbucketApiTest.java
new file mode 100644
index 0000000..44eb198
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/BitbucketApiTest.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.github.scribejava.core.extractors.OAuth2AccessTokenJsonExtractor;
+import org.junit.Before;
+import org.junit.Test;
+
+public class BitbucketApiTest {
+  private BitbucketApi api;
+
+  @Before
+  public void setUp() {
+    api = new BitbucketApi();
+  }
+
+  @Test
+  public void testAccessTokenExtractor() {
+    assertThat(api.getAccessTokenExtractor()).isInstanceOf(OAuth2AccessTokenJsonExtractor.class);
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/CasApiTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/CasApiTest.java
new file mode 100644
index 0000000..17d0ca3
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/CasApiTest.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.github.scribejava.core.extractors.OAuth2AccessTokenExtractor;
+import org.junit.Before;
+import org.junit.Test;
+
+public class CasApiTest {
+  private CasApi api;
+
+  @Before
+  public void setUp() {
+    api = new CasApi("");
+  }
+
+  @Test
+  public void testAccessTokenExtractor() {
+    assertThat(api.getAccessTokenExtractor()).isInstanceOf(OAuth2AccessTokenExtractor.class);
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/DexApiTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/DexApiTest.java
new file mode 100644
index 0000000..160e20c
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/DexApiTest.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.github.scribejava.core.extractors.OAuth2AccessTokenJsonExtractor;
+import org.junit.Before;
+import org.junit.Test;
+
+public class DexApiTest {
+  private DexApi api;
+
+  @Before
+  public void setUp() {
+    api = new DexApi("");
+  }
+
+  @Test
+  public void testAccessTokenExtractor() {
+    assertThat(api.getAccessTokenExtractor()).isInstanceOf(OAuth2AccessTokenJsonExtractor.class);
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/Facebook2ApiTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/Facebook2ApiTest.java
new file mode 100644
index 0000000..b8afae5
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/Facebook2ApiTest.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.github.scribejava.core.extractors.OAuth2AccessTokenJsonExtractor;
+import org.junit.Before;
+import org.junit.Test;
+
+public class Facebook2ApiTest {
+  private Facebook2Api api;
+
+  @Before
+  public void setUp() {
+    api = new Facebook2Api();
+  }
+
+  @Test
+  public void testAccessTokenExtractor() {
+    assertThat(api.getAccessTokenExtractor()).isInstanceOf(OAuth2AccessTokenJsonExtractor.class);
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/GitHub2ApiTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/GitHub2ApiTest.java
new file mode 100644
index 0000000..6b29c59
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/GitHub2ApiTest.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.github.scribejava.core.extractors.OAuth2AccessTokenExtractor;
+import org.junit.Before;
+import org.junit.Test;
+
+public class GitHub2ApiTest {
+  private GitHub2Api api;
+
+  @Before
+  public void setUp() {
+    api = new GitHub2Api(GitHubOAuthService.GITHUB_ROOT_URL);
+  }
+
+  @Test
+  public void testAccessTokenExtractor() {
+    assertThat(api.getAccessTokenExtractor()).isInstanceOf(OAuth2AccessTokenExtractor.class);
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/GitLabApiTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/GitLabApiTest.java
new file mode 100644
index 0000000..86b1c63
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/GitLabApiTest.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.github.scribejava.core.extractors.OAuth2AccessTokenJsonExtractor;
+import org.junit.Before;
+import org.junit.Test;
+
+public class GitLabApiTest {
+  private GitLabApi api;
+
+  @Before
+  public void setUp() {
+    api = new GitLabApi("");
+  }
+
+  @Test
+  public void testAccessTokenExtractor() {
+    assertThat(api.getAccessTokenExtractor()).isInstanceOf(OAuth2AccessTokenJsonExtractor.class);
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/GithubApiUrlTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/GithubApiUrlTest.java
new file mode 100644
index 0000000..ba3f2f7
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/GithubApiUrlTest.java
@@ -0,0 +1,107 @@
+// Copyright (C) 2019 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.Mockito.when;
+
+import com.google.common.base.CharMatcher;
+import com.google.common.base.Strings;
+import com.google.gerrit.extensions.auth.oauth.OAuthServiceProvider;
+import com.google.gerrit.server.config.PluginConfig;
+import com.google.gerrit.server.config.PluginConfigFactory;
+import com.google.inject.Provider;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
+import org.eclipse.jgit.lib.Config;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+@RunWith(MockitoJUnitRunner.class)
+public class GithubApiUrlTest {
+  private static final String PLUGIN_NAME = "gerrit-oauth-provider";
+  private static final String CANONICAL_URL = "https://localhost";
+  private static final String TEST_CLIENT_ID = "test_client_id";
+
+  @Mock private PluginConfigFactory pluginConfigFactoryMock;
+  @Mock private Provider<String> urlProviderMock;
+
+  private OAuthServiceProvider getGithubOAuthProvider(String rootUrl) {
+    PluginConfig pluginConfig =
+        new PluginConfig(PLUGIN_NAME + GitHubOAuthService.CONFIG_SUFFIX, new Config());
+    if (!Strings.isNullOrEmpty(rootUrl)) {
+      pluginConfig.setString(InitOAuth.ROOT_URL, rootUrl);
+    }
+    pluginConfig.setString(InitOAuth.CLIENT_ID, TEST_CLIENT_ID);
+    pluginConfig.setString(InitOAuth.CLIENT_SECRET, "secret");
+    when(pluginConfigFactoryMock.getFromGerritConfig(
+            PLUGIN_NAME + GitHubOAuthService.CONFIG_SUFFIX))
+        .thenReturn(pluginConfig);
+    when(urlProviderMock.get()).thenReturn(CANONICAL_URL);
+
+    return new GitHubOAuthService(pluginConfigFactoryMock, PLUGIN_NAME, urlProviderMock);
+  }
+
+  private String getExpectedUrl(String rootUrl) throws Exception {
+    if (rootUrl == null) {
+      rootUrl = GitHubOAuthService.GITHUB_ROOT_URL;
+    }
+    rootUrl = CharMatcher.is('/').trimTrailingFrom(rootUrl) + "/";
+    return String.format(
+        "%slogin/oauth/authorize?response_type=code&client_id=%s&redirect_uri=%s%s&scope=%s",
+        rootUrl,
+        TEST_CLIENT_ID,
+        URLEncoder.encode(CANONICAL_URL, StandardCharsets.UTF_8.name()),
+        URLEncoder.encode("/oauth", StandardCharsets.UTF_8.name()),
+        URLEncoder.encode(GitHubOAuthService.SCOPE, StandardCharsets.UTF_8.name()));
+  }
+
+  @Test
+  public void nullUrlIsLoaded() throws Exception {
+    String rootUrl = null;
+    OAuthServiceProvider provider = getGithubOAuthProvider(rootUrl);
+    assertThat(provider.getAuthorizationUrl()).isEqualTo(getExpectedUrl(rootUrl));
+  }
+
+  @Test
+  public void githubUrlIsLoaded() throws Exception {
+    String rootUrl = "https://github.com";
+    OAuthServiceProvider provider = getGithubOAuthProvider(rootUrl);
+    assertThat(provider.getAuthorizationUrl()).isEqualTo(getExpectedUrl(rootUrl));
+  }
+
+  @Test
+  public void githubUrlWithTrailingSlashIsLoaded() throws Exception {
+    String rootUrl = "https://github.com/";
+    OAuthServiceProvider provider = getGithubOAuthProvider(rootUrl);
+    assertThat(provider.getAuthorizationUrl()).isEqualTo(getExpectedUrl(rootUrl));
+  }
+
+  @Test
+  public void gheUrlIsLoaded() throws Exception {
+    String rootUrl = "https://git.yourcompany.com";
+    OAuthServiceProvider provider = getGithubOAuthProvider(rootUrl);
+    assertThat(provider.getAuthorizationUrl()).isEqualTo(getExpectedUrl(rootUrl));
+  }
+
+  @Test
+  public void gheUrlWithTrailingSlashIsLoaded() throws Exception {
+    String rootUrl = "https://git.yourcompany.com/";
+    OAuthServiceProvider provider = getGithubOAuthProvider(rootUrl);
+    assertThat(provider.getAuthorizationUrl()).isEqualTo(getExpectedUrl(rootUrl));
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/Google2ApiTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/Google2ApiTest.java
new file mode 100644
index 0000000..72ddaf3
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/Google2ApiTest.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.github.scribejava.core.extractors.OAuth2AccessTokenJsonExtractor;
+import org.junit.Before;
+import org.junit.Test;
+
+public class Google2ApiTest {
+  private Google2Api api;
+
+  @Before
+  public void setUp() {
+    api = new Google2Api();
+  }
+
+  @Test
+  public void testAccessTokenExtractor() {
+    assertThat(api.getAccessTokenExtractor()).isInstanceOf(OAuth2AccessTokenJsonExtractor.class);
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/KeycloakApiTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/KeycloakApiTest.java
new file mode 100644
index 0000000..cb0806d
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/KeycloakApiTest.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.github.scribejava.core.extractors.OAuth2AccessTokenJsonExtractor;
+import org.junit.Before;
+import org.junit.Test;
+
+public class KeycloakApiTest {
+  private KeycloakApi api;
+
+  @Before
+  public void setUp() {
+    api = new KeycloakApi("", "");
+  }
+
+  @Test
+  public void testAccessTokenExtractor() {
+    assertThat(api.getAccessTokenExtractor()).isInstanceOf(OAuth2AccessTokenJsonExtractor.class);
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/Office365ApiTest.java b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/Office365ApiTest.java
new file mode 100644
index 0000000..6bcf313
--- /dev/null
+++ b/devtools/gerrit/gerrit-oauth-provider/src/test/java/com/googlesource/gerrit/plugins/oauth/Office365ApiTest.java
@@ -0,0 +1,35 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.googlesource.gerrit.plugins.oauth;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.github.scribejava.core.extractors.OAuth2AccessTokenJsonExtractor;
+import org.junit.Before;
+import org.junit.Test;
+
+public class Office365ApiTest {
+  private Office365Api api;
+
+  @Before
+  public void setUp() {
+    api = new Office365Api();
+  }
+
+  @Test
+  public void testAccessTokenExtractor() {
+    assertThat(api.getAccessTokenExtractor()).isInstanceOf(OAuth2AccessTokenJsonExtractor.class);
+  }
+}
diff --git a/devtools/gerrit/gerrit-oauth-provider/tools/eclipse/BUILD b/devtools/gerrit/gerrit-oauth-provider/tools/eclipse/BUILD
index e9cb228..252c327 100644
--- a/devtools/gerrit/gerrit-oauth-provider/tools/eclipse/BUILD
+++ b/devtools/gerrit/gerrit-oauth-provider/tools/eclipse/BUILD
@@ -1,4 +1,4 @@
-load("//devtools/gerrit/gerrit-oauth-provider/tools/bzl:classpath.bzl", "classpath_collector")
+load("//tools/bzl:classpath.bzl", "classpath_collector")
 
 classpath_collector(
     name = "main_classpath_collect",