How to Implement OAuth 2.0 Authentication
Build secure OAuth 2.0 authentication with authorization code flow, PKCE, and proper token management.
What You'll Learn
This intermediate-level guide walks you through how to implement oauth 2.0 authentication step by step. Estimated time: 14 min.
Step 1: Understand OAuth 2.0 flows
Learn the Authorization Code flow with PKCE for web apps, Client Credentials for service-to-service, and Device Code for CLI tools.
Step 2: Register your application
Create OAuth applications with each provider, configure redirect URIs, and securely store client credentials.
Step 3: Implement the authorization flow
Build the redirect to provider, handle the callback with code exchange, and store tokens securely using HTTP-only cookies.
Step 4: Manage token lifecycle
Implement access token refresh, handle token expiration gracefully, and revoke tokens on logout.
Step 5: Add security hardening
Validate state parameters to prevent CSRF, use PKCE for public clients, and implement proper error handling for auth failures.
Frequently Asked Questions
Which OAuth flow should I use?▾
Authorization Code with PKCE for web and mobile apps. Client Credentials for server-to-server. Device Code for CLI and IoT. Never use Implicit flow — it is deprecated.
How do I store OAuth tokens securely?▾
Store access tokens in HTTP-only Secure cookies or server-side sessions. Never store tokens in localStorage. Refresh tokens must be stored server-side with encryption.
What if a token is compromised?▾
Revoke the token immediately via the provider API, rotate the refresh token, force re-authentication, and audit recent activity under the compromised session.