JWT Decoder
Decode and inspect JSON Web Tokens (JWT) to view header, payload, and signature information.
JWT Token
About JWT
Structure
Header.Payload.Signature - three Base64 encoded parts
Header
Contains algorithm and token type information
Payload
Contains claims (user data, permissions, expiration)
Signature
Verifies token integrity and authenticity
Security Note
This tool only decodes - signature verification requires the secret key
Common Claims
sub (subject), iss (issuer), exp (expiration), iat (issued at)