JWT and JWKS

Overview

JWT is a compact token format used for authentication and authorization claims. JWKS provides public keys used to verify token signatures.

Validation Flow

sequenceDiagram
    participant Client
    participant API
    participant IdentityProvider
    Client->>API: Bearer JWT
    API->>IdentityProvider: Fetch JWKS
    IdentityProvider-->>API: Public keys
    API-->>API: Validate signature and claims
    API-->>Client: Allow or deny

Practical Example

Validate at least these claims:

• iss (issuer)
• aud (audience)
• exp (expiry)
• nbf (not before)

Production Example

APIs cache JWKS with refresh logic and key-rotation handling to avoid authorization outages during signing-key rollover.

Common Pitfalls

• Trusting token content without signature verification
• Ignoring audience checks
• No handling for rotated keys

Key Takeaways

• JWT security depends on strict validation.
• JWKS enables safe key distribution and rotation.
• Claim checks are mandatory for secure API authorization.