jwt is a Go implementation of JSON Web Tokens (JWT) that handles both parsing and verification as well as generation and signing of tokens.
The library solves the problem of securely creating and validating JWT tokens in Go applications. It supports multiple signing algorithms including HMAC SHA, RSA, RSA-PSS, and ECDSA, with extensibility hooks for adding custom algorithms. The implementation enforces that key types match the expected algorithm to help developers avoid common security pitfalls, though the README emphasizes that users should independently verify the algorithm presented in a token matches what they expect.
Developers adopting this tool should be aware that it maintains backward compatibility with the original upstream library while having undergone significant maintenance transitions. The project moved to dedicated open source maintainers after the original author suggested migration. Version 4.0.0 added Go module support while maintaining backward compatibility with older versions, and version 5.0.0 introduced major improvements to token validation but is not entirely backward compatible. The library's support for Go versions aligns with Go's official release policy, supporting each major version until two newer releases exist.
The project maintains active engagement with security concerns, documenting known vulnerabilities and providing migration guidance for users upgrading between major versions. Development activity shows sustained attention to the library's role in authentication workflows, with comprehensive documentation and examples provided on a dedicated website. The maintainers have established clear policies around Go version support tied to upstream security practices rather than arbitrary timelines.
