Google OAuth

Users can sign in or sign up with Google using the google provider from next-auth / Auth.js, configured in src/lib/auth/auth.ts.

Client UI

• Component: src/components/auth/GoogleAuth.tsx
• Behavior: signIn("google", { callbackUrl: appConfig.auth.afterLogin, redirect: false }); on success, navigates using result.url or falls back to appConfig.auth.newUser.
• Usage: Embedded on login (src/app/(auth)/login/login-form.tsx) and register (src/app/(auth)/register/register-form.tsx) flows.

TIP

Ensure callbackUrl / OAuth redirect URIs match your deployment URL in the Google Cloud Console.

Server configuration

• Provider: Google({ clientId, clientSecret, allowDangerousEmailAccountLinking: true }) in src/lib/auth/auth.ts.
• Adapter: PrismaAdapter(prisma) stores OAuth accounts and links them to users.
• Session: JWT strategy; user profile fields flow through callbacks in auth.ts.

allowDangerousEmailAccountLinking relaxes linking when an email already exists in your database — understand the security trade-offs before shipping to production.

Environment variables

Variable	Purpose
GOOGLE_CLIENT_ID	OAuth 2.0 client ID
GOOGLE_CLIENT_SECRET	OAuth 2.0 client secret

Shared with credentials auth:

Variable	Purpose
AUTH_SECRET	Session signing (appConfig.auth.secret)
AUTH_URL / NEXT_PUBLIC_APP_URL / VERCEL_URL	Canonical URLs for redirects (see src/config.ts)

Post-link behavior

An events.linkAccount handler in src/lib/auth/auth.ts updates emailVerified for existing users when Google links, if applicable.

File map (Google)

Role	Path
Google button & signIn("google")	src/components/auth/GoogleAuth.tsx
Google provider + callbacks + events	src/lib/auth/auth.ts
Auth API	src/app/api/auth/[...nextauth]/route.ts
Login / register shells	src/app/(auth)/login/login-form.tsx, src/app/(auth)/register/register-form.tsx
App URLs	src/config.ts → appConfig.auth

WARNING

Credential and Google flows share the same user table; email collisions and linking behavior depend on allowDangerousEmailAccountLinking and your registration rules in register-actions.ts.