Google Workspace APIs

Status: Production Ready Last Updated: 2026-01-09 Dependencies: Cloudflare Workers (recommended), Google Cloud Project Skill Version: 1.0.0

Quick Reference

API Common Use Cases Reference

Gmail Email automation, inbox management gmail-api.md

Calendar Event management, scheduling calendar-api.md

Drive File storage, sharing drive-api.md

Sheets Spreadsheet data, reporting sheets-api.md

Docs Document generation docs-api.md

Chat Bots, webhooks, spaces chat-api.md

Meet Video conferencing meet-api.md

Forms Form responses, creation forms-api.md

Tasks Task management tasks-api.md

Admin SDK User/group management admin-sdk.md

People Contacts management people-api.md

Shared Authentication Patterns

All Google Workspace APIs use the same authentication mechanisms. Choose based on your use case.

Option 1: OAuth 2.0 (User Context)

Best for: Acting on behalf of a user, accessing user-specific data.

// Authorization URL const authUrl = new URL('https://accounts.google.com/o/oauth2/v2/auth') authUrl.searchParams.set('client_id', env.GOOGLE_CLIENT_ID) authUrl.searchParams.set('redirect_uri', ${env.BASE_URL}/callback) authUrl.searchParams.set('response_type', 'code') authUrl.searchParams.set('scope', SCOPES.join(' ')) authUrl.searchParams.set('access_type', 'offline') // For refresh tokens authUrl.searchParams.set('prompt', 'consent') // Force consent for refresh token

// Token exchange async function exchangeCode(code: string): Promise<TokenResponse> { const response = await fetch('https://oauth2.googleapis.com/token', { method: 'POST', headers: { 'Content-Type': 'application/x-www-form-urlencoded' }, body: new URLSearchParams({ code, client_id: env.GOOGLE_CLIENT_ID, client_secret: env.GOOGLE_CLIENT_SECRET, redirect_uri: ${env.BASE_URL}/callback, grant_type: 'authorization_code', }), }) return response.json() }

// Refresh token async function refreshToken(refresh_token: string): Promise<TokenResponse> { const response = await fetch('https://oauth2.googleapis.com/token', { method: 'POST', headers: { 'Content-Type': 'application/x-www-form-urlencoded' }, body: new URLSearchParams({ refresh_token, client_id: env.GOOGLE_CLIENT_ID, client_secret: env.GOOGLE_CLIENT_SECRET, grant_type: 'refresh_token', }), }) return response.json() }

Critical:

• Always request access_type=offline for refresh tokens

• Use prompt=consent to ensure refresh token is returned

• Store refresh tokens securely (Cloudflare KV or D1)

• Access tokens expire in ~1 hour

Option 2: Service Account (Server-to-Server)

Best for: Backend automation, no user interaction, domain-wide delegation.

import { SignJWT } from 'jose'

async function getServiceAccountToken( serviceAccount: ServiceAccountKey, scopes: string[] ): Promise<string> { const now = Math.floor(Date.now() / 1000)

// Create JWT const jwt = await new SignJWT({ iss: serviceAccount.client_email, scope: scopes.join(' '), aud: 'https://oauth2.googleapis.com/token', iat: now, exp: now + 3600, }) .setProtectedHeader({ alg: 'RS256', typ: 'JWT' }) .sign(await importPKCS8(serviceAccount.private_key, 'RS256'))

// Exchange JWT for access token const response = await fetch('https://oauth2.googleapis.com/token', { method: 'POST', headers: { 'Content-Type': 'application/x-www-form-urlencoded' }, body: new URLSearchParams({ grant_type: 'urn:ietf:params:oauth:grant-type:jwt-bearer', assertion: jwt, }), })

const data = await response.json() return data.access_token }

Domain-Wide Delegation (impersonate users):

const jwt = await new SignJWT({ iss: serviceAccount.client_email, sub: 'user@domain.com', // User to impersonate scope: scopes.join(' '), aud: 'https://oauth2.googleapis.com/token', iat: now, exp: now + 3600, })

Setup Required:

• Create service account in Google Cloud Console

• Download JSON key file

• Enable domain-wide delegation in Admin Console (if impersonating)

• Store key as Cloudflare secret (JSON stringified)

Common Rate Limits

All Google Workspace APIs enforce quotas. These are approximate - check each API's specific limits.

Per-User Limits (OAuth)

API Reads Writes Notes

Gmail 250/user/sec 250/user/sec Aggregate across all methods

Calendar 500/user/100sec 500/user/100sec Per calendar

Drive 1000/user/100sec 1000/user/100sec

Sheets 100/user/100sec 100/user/100sec Lower than others

Per-Project Limits

API Daily Quota Per-Minute Notes

Gmail 1B units Varies Unit-based (send = 100 units)

Calendar 1M queries 500/sec

Drive 1B queries 1000/sec

Sheets Unlimited 500/user/100sec

Handling Rate Limits

async function withRetry<T>( fn: () => Promise<T>, maxRetries = 5 ): Promise<T> { for (let i = 0; i < maxRetries; i++) { try { return await fn() } catch (error: any) { const status = error.status || error.code

  if (status === 429 || status === 503) {
    // Rate limited or service unavailable
    const retryAfter = error.headers?.get('Retry-After') || Math.pow(2, i)
    await new Promise(r => setTimeout(r, retryAfter * 1000))
    continue
  }

  if (status === 403 && error.message?.includes('rateLimitExceeded')) {
    // Quota exceeded - exponential backoff
    await new Promise(r => setTimeout(r, Math.pow(2, i) * 1000))
    continue
  }

  throw error
}

} throw new Error('Max retries exceeded') }

Batch Requests

Most Google APIs support batching multiple requests into one HTTP call.

async function batchRequest( accessToken: string, requests: BatchRequestItem[] ): Promise<BatchResponse[]> { const boundary = 'batch_boundary'

let body = '' requests.forEach((req, i) => { body += --${boundary}\r\n body += 'Content-Type: application/http\r\n' body += Content-ID: <item${i}>\r\n\r\n body += ${req.method} ${req.path} HTTP/1.1\r\n body += 'Content-Type: application/json\r\n\r\n' if (req.body) body += JSON.stringify(req.body) body += '\r\n' }) body += --${boundary}--

const response = await fetch('https://www.googleapis.com/batch/v1', { method: 'POST', headers: { 'Authorization': Bearer ${accessToken}, 'Content-Type': multipart/mixed; boundary=${boundary}, }, body, })

// Parse multipart response... return parseBatchResponse(await response.text()) }

Limits:

• Max 100 requests per batch (most APIs)

• Max 1000 requests per batch (some APIs like Drive)

• Each request in batch counts toward quota

Cloudflare Workers Configuration

// wrangler.jsonc { "name": "google-workspace-mcp", "main": "src/index.ts", "compatibility_date": "2026-01-03", "compatibility_flags": ["nodejs_compat"],

// Store OAuth tokens "kv_namespaces": [ { "binding": "TOKENS", "id": "xxx" } ],

// Or use D1 for structured storage "d1_databases": [ { "binding": "DB", "database_name": "workspace-mcp", "database_id": "xxx" } ] }

Secrets to set:

echo "your-client-id" | npx wrangler secret put GOOGLE_CLIENT_ID echo "your-client-secret" | npx wrangler secret put GOOGLE_CLIENT_SECRET

For service accounts:

cat service-account.json | npx wrangler secret put GOOGLE_SERVICE_ACCOUNT

Common Errors

Error: "invalid_grant" on Token Refresh

Cause: Refresh token revoked or expired (6 months of inactivity) Fix: Re-authenticate user, request new refresh token

Error: "access_denied" on OAuth

Cause: App not verified, or user not in test users list Fix: Add user to OAuth consent screen test users, or complete app verification

Error: "insufficientPermissions" (403)

Cause: Missing required scope Fix: Check scopes in authorization URL, re-authenticate with correct scopes

Error: "rateLimitExceeded" (403)

Cause: Quota exceeded Fix: Implement exponential backoff, reduce request frequency, request quota increase

Error: "notFound" (404) on Known Resource

Cause: Using wrong API version, or resource in trash Fix: Check API version in URL, check trash for deleted items

API-Specific Guides

Detailed patterns for each API are in the references/ directory. Load these when working with specific APIs.

Gmail API

See references/gmail-api.md

• Message CRUD, labels, threads

• MIME handling, attachments

• Push notifications (Pub/Sub)

Calendar API

See references/calendar-api.md

• Events CRUD, recurring events

• Free/busy queries

• Calendar sharing

Drive API

See references/drive-api.md

• File upload/download

• Permissions, sharing

• Search queries

Sheets API

See references/sheets-api.md

• Reading/writing cells

• A1 notation, ranges

• Batch updates

Chat API

See references/chat-api.md

• Bots, webhooks

• Cards v2, interactive forms

• Spaces, members, reactions

(Additional API references added as MCP servers are built)

Package Versions (Verified 2026-01-09)

{ "devDependencies": { "@cloudflare/workers-types": "^4.20260109.0", "wrangler": "^4.58.0", "jose": "^6.1.3" } }

Official Documentation

• Google Workspace APIs: https://developers.google.com/workspace

• OAuth 2.0: https://developers.google.com/identity/protocols/oauth2

• Service Accounts: https://cloud.google.com/iam/docs/service-accounts

• API Explorer: https://developers.google.com/apis-explorer

• Quotas Dashboard: https://console.cloud.google.com/iam-admin/quotas

Skill Roadmap

APIs documented as MCP servers are built:

• Gmail API

• Calendar API

• Drive API

• Sheets API

• Docs API

• Chat API (migrated from google-chat-api skill)

• Meet API

• Forms API

• Tasks API

• Admin SDK

• People API