OIDC Playground (Go + Clerk)

Minimal Go web app demonstrating OAuth 2.0 + OIDC login with Clerk as the identity provider. It uses the Authorization Code + PKCE flow and fetches the authenticated user's profile via Clerk's /oauth/userinfo endpoint.

References: Clerk OAuth/OIDC docs

Prerequisites

• Go 1.21+ (tested with 1.25)
• A Clerk instance with an OAuth application configured

Collect from Clerk Dashboard:

• CLERK_FRONTEND_API_URL (e.g. https://verb-noun-00.clerk.accounts.dev or https://clerk.<YOUR_APP_DOMAIN>.com)
• OAuth app Client ID
• Add redirect URL: http://localhost:3009/callback

Configure

Create .env at repo root:

CLERK_FRONTEND_API_URL=YOUR_FRONTEND_API_URL
CLERK_OAUTH_CLIENT_ID=YOUR_CLIENT_ID
OAUTH_REDIRECT_URI=http://localhost:3009/callback
OAUTH_SCOPE=openid profile email
COOKIE_SECURE=false

Run

go run .

Visit http://localhost:3009 then click /login. After authenticating with Clerk, you'll be redirected to /hello, which returns a JSON payload including your Clerk /oauth/userinfo response.

Notes

• This demo stores tokens in HTTP-only cookies for simplicity. For production, store tokens server-side, set Secure cookies, and consider validating the ID token using your instance JWKS and checking claims.
• The app only calls /oauth/userinfo with the access token, which aligns with Clerk's docs for obtaining profile information.