/google

name: google
description: Emulated Google OAuth 2.0, OpenID Connect, Gmail, Calendar, and Drive for local development and testing. Use when the user needs to test Google sign-in locally, emulate OIDC discovery, handle Google token exchange, configure Google OAuth clients, work with Gmail messages/drafts/threads/labels, manage Calendar events, upload or list Drive files, or work with Google userinfo without hitting real Google APIs. Triggers include "Google OAuth", "emulate Google", "mock Google login", "test Google sign-in", "OIDC emulator", "Google OIDC", "Gmail API", "Google Calendar", "Google Drive", "local Google auth", or any task requiring a local Google API.
allowed-tools: Bash(npx emulate:*), Bash(curl:*)

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

# 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

| Real Google URL | Emulator URL | |-----------------|-------------| | `https://accounts.google.com/o/oauth2/v2/auth` | `$GOOGLE_EMULATOR_URL/o/oauth2/v2/auth` | | `https://oauth2.googleapis.com/token` | `$GOOGLE_EMULATOR_URL/oauth2/token` | | `https://www.googleapis.com/oauth2/v2/userinfo` | `$GOOGLE_EMULATOR_URL/oauth2/v2/userinfo` | | `https://accounts.google.com/.well-known/openid-configuration` | `$GOOGLE_EMULATOR_URL/.well-known/openid-configuration` | | `https://www.googleapis.com/oauth2/v3/certs` | `$GOOGLE_EMULATOR_URL/oauth2/v3/certs` | | `https://gmail.googleapis.com/gmail/v1/...` | `$GOOGLE_EMULATOR_URL/gmail/v1/...` | | `https://www.googleapis.com/calendar/v3/...` | `$GOOGLE_EMULATOR_URL/calendar/v3/...` | | `https://www.googleapis.com/drive/v3/...` | `$GOOGLE_EMULATOR_URL/drive/v3/...` |

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=...`

Auth.js / NextAuth.js

import Google from '@auth/core/providers/google'

Google({
  clientId: process.env.GOOGLE_CLIENT_ID,
  clientSecret: process.env.GOOGLE_CLIENT_SECRET,
  authorization: {
    url: `${process.env.GOOGLE_EMULATOR_URL}/o/oauth2/v2/auth`,
    params: { scope: 'openid email profile' },
  },
  token: {
    url: `${process.env.GOOGLE_EMULATOR_URL}/oauth2/token`,
  },
  userinfo: {
    url: `${process.env.GOOGLE_EMULATOR_URL}/oauth2/v2/userinfo`,
  },
})

Passport.js

import { Strategy as GoogleStrategy } from 'passport-google-oauth20'

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

new GoogleStrategy({
  clientID: process.env.GOOGLE_CLIENT_ID,
  clientSecret: process.env.GOOGLE_CLIENT_SECRET,
  callbackURL: 'http://localhost:3000/api/auth/callback/google',
  authorizationURL: `${GOOGLE_URL}/o/oauth2/v2/auth`,
  tokenURL: `${GOOGLE_URL}/oauth2/token`,
  userProfileURL: `${GOOGLE_URL}/oauth2/v2/userinfo`,
}, verifyCallback)

Seed Config

google:
  users:
    - email: testuser@gmail.com
      name: Test User
      given_name: Test
      family_name: User
      picture: https://lh3.googleusercontent.com/a/default-user
      email_verified: true
      locale: en
    - email: dev@example.com
      name: Developer
    - email: admin@acme.com
      name: Admin
      hd: acme.com
  oauth_clients:
    - client_id: my-client-id.apps.googleusercontent.com
      client_secret: GOCSPX-secret
      name: My App
      redirect_uris:
        - http://localhost:3000/api/auth/callback/google
  labels:
    - id: Label_ops
      user_email: testuser@gmail.com
      name: Ops/Review
      color_background: "#DDEEFF"
      color_text: "#111111"
  messages:
    - id: msg_welcome
      user_email: testuser@gmail.com
      thread_id: thr_welcome
      from: "welcome@example.com"
      to: testuser@gmail.com
      subject: Welcome to the Gmail emulator
      body_text: You can now test Gmail flows locally.
      label_ids: [INBOX, UNREAD, CATEGORY_UPDATES]
      date: "2025-01-04T10:00:00.000Z"
  calendars:
    - id: primary
      user_email: testuser@gmail.com
      summary: testuser@gmail.com
      primary: true
      selected: true
      time_zone: UTC
  calendar_events:
    - id: evt_kickoff
      user_email: testuser@gmail.com
      calendar_id: primary
      summary: Project Kickoff
      start_date_time: "2025-01-10T09:00:00.000Z"
      end_date_time: "2025-01-10T09:30:00.000Z"
      attendees:
        - email: testuser@gmail.com
          display_name: Test User
      conference_entry_points:
        - entry_point_type: video
          uri: https://meet.google.com/example
          label: Google Meet
      hangout_link: https://meet.google.com/example
  drive_items:
    - id: drv_docs
      user_email: testuser@gmail.com
      name: Docs
      mime_type: application/vnd.google-apps.folder
      parent_ids: [root]
    - id: drv_readme
      user_email: testuser@gmail.com
      name: README.md
      mime_type: text/markdown
      parent_ids: [drv_docs]
      data: "# Hello World"

When no OAuth clients are configured, the emulator accepts any `cl