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How to Integrate with

February 20, 2026

Google Drive is one of the most widely adopted file storage platforms in the enterprise. A production-grade Google Drive API integration allows your product to upload, download, search, and manage files within your customers' Drive environments securely and at scale.

However, integrating Google Drive in a multi-tenant B2B SaaS application involves more than enabling an API and sending REST requests. You must implement OAuth correctly, choose least-privilege scopes, manage pagination and large file transfers, and design for reliable change detection.

This guide covers:

  1. How to integrate directly with the Google Drive API
  2. The operational considerations you will own
  3. How to integrate Google Drive using Unified's File Storage API
  4. When to build directly vs use an integration layer

Direct Google Drive API Integration

Step 1: Create a Google Cloud Project and Enable the Drive API

Begin in the Google Cloud Console.

  1. Create a new project (or select an existing one).
  2. Navigate to APIs & Services → Library.
  3. Search for Google Drive API.
  4. Click Enable.

Google documents this process in the official Drive API quickstart guide.

Before creating credentials, configure the OAuth consent screen:

  1. Go to APIs & Services → OAuth consent screen.
  2. Choose Internal (Workspace-only) or External (public SaaS).
  3. Provide:
    • App name
    • Support email
    • Developer contact information
  4. Add authorized domains and privacy policy links if required.

Google explains OAuth setup for web server applications in its OAuth 2.0 Web Server Applications documentation.

If your app requests sensitive or restricted scopes, Google may require verification before production release.

Step 3: Select the Correct OAuth Scopes

Scopes define what your application can access.

Common Google Drive scopes include:

  • https://www.googleapis.com/auth/drive.readonly
  • https://www.googleapis.com/auth/drive.file
  • https://www.googleapis.com/auth/drive
  • openid, profile, email

Google recommends selecting the least permissive scope possible. The official Drive API scope reference explains the differences between metadata access, per-file access, and full Drive access.

For most SaaS integrations:

  • drive.file is preferred for write access limited to files created or opened by your app.
  • drive.readonly is appropriate for ingestion and indexing use cases.

Step 4: Create OAuth Credentials

In APIs & Services → Credentials:

  1. Click Create Credentials → OAuth client ID.
  2. Select Web application for server-side SaaS integrations.
  3. Provide:
    • Authorized redirect URI
    • Authorized JavaScript origins (if applicable)

Example redirect URI:

https://yourapp.com/oauth/google/callback

After creation, Google provides:

  • Client ID
  • Client Secret

These are required for implementing the OAuth authorization code flow.

Step 5: Implement the OAuth 2.0 Authorization Code Flow

For SaaS products, the standard approach is the OAuth 2.0 authorization code flow.

High-level sequence:

  1. Redirect user to Google's authorization endpoint.
  2. User grants requested scopes.
  3. Google redirects back with an authorization code.
  4. Your backend exchanges the code for:
    • Access token
    • Refresh token

Google documents the full token exchange process in the OAuth 2.0 Web Server Flow guide.

Access tokens expire (typically within one hour). Your application must securely store refresh tokens and implement automatic refresh logic.

Core Google Drive API v3 Endpoints

All authenticated requests require:

Authorization: Bearer {access_token}

List Files

GET https://www.googleapis.com/drive/v3/files

Common parameters:

  • q (search query)
  • pageSize
  • pageToken
  • fields
  • supportsAllDrives
  • includeItemsFromAllDrives

Pagination uses pageSize and nextPageToken, not offset-based paging.

Reference: Drive files.list documentation

Get File Metadata

GET https://www.googleapis.com/drive/v3/files/{fileId}

Reference: Drive files.get documentation

Download File Content

GET https://www.googleapis.com/drive/v3/files/{fileId}?alt=media

Google Workspace documents (Docs, Sheets, Slides) must be exported instead:

GET https://www.googleapis.com/drive/v3/files/{fileId}/export?mimeType=application/pdf

Reference: Download and export files guide

Upload File

POST https://www.googleapis.com/upload/drive/v3/files

Upload types:

  • Simple upload
  • Multipart upload
  • Resumable upload (recommended for large files)

Reference: Drive upload documentation

Change Signals in Google Drive

Google Drive provides multiple ways to detect changes.

Push Notifications (Watch Channels)

Drive can send HTTPS notifications to your endpoint when a watched file or folder changes.

Reference: Drive Push Notifications guide

This approach requires maintaining channel IDs and expiration handling.

Changes Feed (Polling)

The changes resource enables incremental synchronization via page tokens.

Reference: Drive changes.list documentation

This is often used for:

  • Initial full sync
  • Catch-up processing
  • Recovery after downtime

Pub/Sub Events

Google Drive can publish events to Google Cloud Pub/Sub for scalable, asynchronous processing.

Reference: Drive Events overview

Pub/Sub is recommended for high-volume or distributed architectures.

Operational Complexity of Direct Google Drive Integration

A production-ready integration requires:

  • OAuth lifecycle management
  • Secure token storage and rotation
  • Scope verification compliance
  • Handling shared drives vs My Drive
  • Export logic for Google-native document formats
  • Pagination management (nextPageToken)
  • Retry logic with exponential backoff
  • Change detection architecture

For a single internal workflow, this may be manageable.

For a multi-tenant SaaS platform serving many Google Drive customers, this becomes sustained infrastructure work.

Integrating Google Drive via Unified's File Storage API

If your roadmap includes Google Drive plus other storage providers (Box, Dropbox, OneDrive), maintaining separate OAuth logic and change detection flows increases long-term complexity.

Unified provides a File Storage API that standardizes file operations across providers.

Step 1: Register Google OAuth for Unified

When integrating via Unified, configure your Google OAuth redirect URI as:

https://api.unified.to/oauth/code

Unified's setup guide is available in the Google OAuth credentials guide.

Unified scope mapping for Google Drive includes:

  • storage_file_read → openid, profile, email, drive.readonly
  • storage_file_write → openid, profile, email, drive

Step 2: Activate Google Drive in Unified

In your Unified workspace:

  1. Activate Google Drive.
  2. Enter your Client ID and Client Secret.
  3. Authorize a user account.
  4. Receive a connection_id.

Step 3: Call Unified's File Storage API

Example:

GET https://api.unified.to/storage/file/{connection_id}?limit=100
Authorization: Bearer YOUR_UNIFIED_API_KEY

Supported methods:

  • list
  • get
  • create
  • update
  • remove

Readable fields include:

  • id
  • name
  • mime_type
  • size
  • parent_id
  • permissions
  • download_url
  • created_at
  • updated_at

Writable fields include:

  • name
  • parent_id
  • mime_type
  • data

Unified delivers change events for Google Drive using virtual webhooks:

  • created
  • updated
  • deleted

This provides webhook-style notifications without requiring you to build Pub/Sub consumers.

If you're evaluating broader integration architecture, review our overview of Unified APIs for SaaS integrations and AI copilots.

Direct vs Unified — When to Choose Each

Build Directly If

  • Google Drive is your only storage integration
  • You require deep Drive-specific capabilities
  • You want full control over OAuth and event infrastructure

Use Unified If

  • You support multiple storage providers
  • You want one normalized file storage surface
  • You prefer not to build OAuth lifecycle logic
  • You want webhook-style delivery without managing Pub/Sub
  • You want usage-based pricing rather than per-connection billing

Final Thoughts

Google Drive API integration is straightforward at the endpoint level. The engineering complexity lies in authentication, pagination, change detection, and secure multi-tenant architecture.

If file storage is part of your core product surface, designing your integration architecture carefully will determine how quickly you can ship and how reliably you can scale.

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