OAuth 2.1

Understanding OAuth 2.1 and its improvements over OAuth 2.0

What is OAuth 2.1?

OAuth 2.1 is the latest iteration of the OAuth authorization framework. It consolidates best practices and security improvements from OAuth 2.0, removing deprecated features and making PKCE mandatory.

Key Improvements

Mandatory PKCE

All clients must use PKCE for authorization code flow

No Implicit Flow

Deprecated implicit and password grants removed

Redirect URI Matching

Exact matching required, no wildcards

Security First

Built-in protection against common attacks

OAuth 2.1 vs OAuth 2.0

Feature	OAuth 2.0	OAuth 2.1
PKCE	Optional	Mandatory
Implicit Flow	Supported	Removed
Password Grant	Supported	Removed
Redirect URI	Substring match	Exact match
Refresh Token Rotation	Optional	Recommended

Why OAuth 2.1?

1. Enhanced Security

   PKCE prevents authorization code interception attacks

2. Simplified Spec

   Removes deprecated and insecure flows
3. Modern Best Practices

   Incorporates years of real-world experience

4. Future-Proof

   Designed for current and future security threats

Learn More

PKCE Explained

Deep dive into PKCE implementation

Authentication Flow

Complete OAuth 2.1 flow with Auth-Agent