diff --git a/games/factorio/modproxy/modportal/BUILD.bazel b/games/factorio/modproxy/modportal/BUILD.bazel
new file mode 100644
index 0000000..051aec7
--- /dev/null
+++ b/games/factorio/modproxy/modportal/BUILD.bazel
@@ -0,0 +1,12 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["modportal.go"],
+    importpath = "code.hackerspace.pl/hscloud/games/factorio/modproxy/modportal",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@org_golang_google_grpc//codes:go_default_library",
+        "@org_golang_google_grpc//status:go_default_library",
+    ],
+)
diff --git a/games/factorio/modproxy/modportal/modportal.go b/games/factorio/modproxy/modportal/modportal.go
new file mode 100644
index 0000000..5e507fd
--- /dev/null
+++ b/games/factorio/modproxy/modportal/modportal.go
@@ -0,0 +1,98 @@
+package modportal
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+type Mod struct {
+	Name     string    `json:"name"`
+	Releases []Release `json:"releases"`
+}
+
+type Release struct {
+	DownloadURL string   `json:"download_url"`
+	FileName    string   `json:"file_name"`
+	Info        InfoJSON `json:"info_json"`
+	ReleasedAt  string   `json:"released_at"`
+	SHA1        string   `json:"sha1"`
+	Version     string   `json:"version"`
+}
+
+type InfoJSON struct {
+	Dependencies    []string `json:"dependencies"`
+	FactorioVersion string   `json:"factorio_json"`
+}
+
+func GetMod(ctx context.Context, name string) (*Mod, error) {
+	url := fmt.Sprintf("https://mods.factorio.com/api/mods/%s", url.PathEscape(name))
+
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, status.Errorf(codes.Internal, "NewRequest(%q): %v", url, err)
+	}
+
+	req = req.WithContext(ctx)
+	res, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, status.Errorf(codes.Unavailable, "Do(req{%q}): %v", url, err)
+	}
+	defer res.Body.Close()
+
+	if res.StatusCode != 200 {
+		return nil, status.Errorf(codes.Unavailable, "mod portal responded with code: %d", res.StatusCode)
+	}
+
+	mod := &Mod{}
+	err = json.NewDecoder(res.Body).Decode(mod)
+	if err != nil {
+		return nil, status.Errorf(codes.Internal, "could not decode mod portal JSON: %v", err)
+	}
+
+	return mod, nil
+}
+
+func (m *Mod) ReleaseBySHA1(sha1 string) *Release {
+	for _, r := range m.Releases {
+		if r.SHA1 == sha1 {
+			return &r
+		}
+	}
+	return nil
+}
+
+func (m *Mod) ReleaseByVersion(version string) *Release {
+	for _, r := range m.Releases {
+		if r.Version == version {
+			return &r
+		}
+	}
+	return nil
+}
+
+func (r *Release) Download(ctx context.Context, username, token string) (io.ReadCloser, error) {
+	url := fmt.Sprintf("https://mods.factorio.com/%s?username=%s&token=%s", r.DownloadURL, username, token)
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, status.Errorf(codes.Internal, "NewRequest(%q): %v", url, err)
+	}
+
+	req = req.WithContext(ctx)
+	res, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, status.Errorf(codes.Unavailable, "Do(req{%q}): %v", url, err)
+	}
+	if res.StatusCode != 200 {
+		res.Body.Close()
+		return nil, status.Errorf(codes.Unavailable, "mod portal responded with code: %d", res.StatusCode)
+	}
+
+	return res.Body, err
+}