google

Google OAuth 2.0 / OIDC + Gmail, Calendar & Drive Emulator

OAuth 2.0 and OpenID Connect emulation with authorization code flow, PKCE support, ID tokens, OIDC discovery, refresh tokens, plus Gmail, Google Calendar, and Google Drive REST API surfaces.

Start

Local listeners bind to 127.0.0.1 by default. For access from containers or other machines, pass --host 0.0.0.0 to the CLI or hostname: '0.0.0.0' to createEmulator. Configure --base-url or baseUrl for advertised URLs reachable by those clients.

# Google only
npx emulate --service google

# Default port
# http://localhost:4002

Or programmatically:

import { createEmulator } from 'emulate'

const google = await createEmulator({ service: 'google', port: 4002 })
// google.url === 'http://localhost:4002'

Pointing Your App at the Emulator

Environment Variable

GOOGLE_EMULATOR_URL=http://localhost:4002

OAuth URL Mapping

google-auth-library (Node.js)

import { OAuth2Client } from 'google-auth-library'

const GOOGLE_URL = process.env.GOOGLE_EMULATOR_URL ?? 'https://accounts.google.com'

const client = new OAuth2Client({
  clientId: process.env.GOOGLE_CLIENT_ID,
  clientSecret: process.env.GOOGLE_CLIENT_SECRET,
  redirectUri: 'http://localhost:3000/api/auth/callback/google',
})

const emulatorAuthorizeUrl = `${GOOGLE_URL}/o/oauth2/v2/auth?client_id=${process.env.GOOGLE_CLIENT_ID}&redirect_uri=...&scope=openid+email+profile&response_type=code&state=...`