How to handle JWT in Go

JSON Web Tokens (JWTs) are widely used in modern applications for representing identity, session state, and authorization, allowing secure exchange of tamper-resistant information between services without traditional server-side sessions. In Go, JWT handling offers granular control over tasks such as token parsing, verification, and key management, requiring developers to implement these functions manually. This guide comprehensively explores JWT usage in Go, covering aspects like HS256/RS256 verification, JSON Web Key Sets (JWKS), middleware design, key rotation strategies, and common pitfalls. It highlights the importance of cryptographic key management, recommending the use of JWKS for efficient key distribution and rotation, and discusses the use of the jwt-go library to handle token parsing, claims validation, and signature verification. Additionally, the guide provides detailed instructions on generating RSA keys, creating JWTs with standard and custom claims, verifying JWTs, and implementing a JWT middleware in a Go web server. It emphasizes best practices such as always verifying signatures, using asymmetric signing methods, validating critical claims, and ensuring secure storage of sensitive information. The guide also suggests leveraging solutions like WorkOS for managing upstream identity flows and token issuance, particularly in enterprise environments.