JWT Parser
Paste a JWT to inspect its Base64URL segments, formatted JOSE header, claims, and signature bytes locally in your browser.
Parse a JWT
The token is split into Header, Payload, and Signature. Parsing shows content; it does not verify authenticity.
Header
JOSE metadata such as the algorithm and token type used by the token.
Payload
The claims carried by the token, such as subject, issuer, roles, and timestamps.
Signature
Integrity data calculated from the encoded header and payload using a key.
Parsed JWT
Parsed sections will appear here
Paste a compact JWT and run the parser to view its formatted JSON sections.
How the JWT parser works
JWT compact serialization stores the JOSE header, claims payload, and signature as dot-separated Base64URL values. DecodeLens parses each section in a local worker and formats JSON without persisting the token.
Current scope
- Parses JWT/JWS compact serialization and formats Header and Payload JSON.
- Shows iat, nbf, and exp timestamp claims as local date and time when present.
- Does not verify signatures yet and never labels a parsed token as valid.
- Five-part JWE tokens, remote JWKS fetching, and key-based verification are not included in this parser version.