JWT Decoding and Validation: How to Securely Parse and Verify Your Tokens
JSON Web Tokens (JWT) have become a cornerstone of modern web authentication and authorization systems. They provide a compact, URL-safe means of representing claims to be transferred between parties. However, the security of your application hinges on how you decode and validate these tokens. In this article, we’ll explore the process of securely parsing and verifying JWT tokens, ensuring your application remains protected against potential vulnerabilities. Visual Overview: graph LR subgraph JWT Token A[Header] --> B[Payload] --> C[Signature] end A --> D["{ alg: RS256, typ: JWT }"] B --> E["{ sub, iss, exp, iat, ... }"] C --> F["HMACSHA256(base64(header) + base64(payload), secret)"] style A fill:#667eea,color:#fff style B fill:#764ba2,color:#fff style C fill:#f093fb,color:#fff Understanding JWT Structure Before diving into decoding and validation, it’s essential to understand the structure of a JWT token. A JWT consists of three parts, separated by dots (.): ...