JWT Decoder
Deconstruct and read JSON Web Token (JWT) payloads. No token data is sent to external servers; decoding occurs entirely on your device.
Note: This tool parses claims locally. It does not verify cryptographic signatures.
About JSON Web Tokens (JWT)
JSON Web Tokens are a compact, URL-safe means of representing claims to be transferred between two parties. JWTs are structured with three dot-separated Base64Url segments: Header, Payload, and Signature.
Understanding the segments:
- Header: Typically specifies the token type (JWT) and the hashing algorithm used (e.g. HS256, RS256).
- Payload: Contains the claims, which are statements about the user or session entity (e.g. subject ID, expiry timestamps, scopes).
- Signature: Used by server systems to cryptographically verify that the token was not tampered with.
Security Warning: This tool parses Base64 payloads client-side for debugging. Do not paste tokens containing sensitive production database passwords or access keys into public websites.