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JWT Decoder

Decode and inspect JSON Web Tokens instantly. Your token never leaves your browser.

What is a JWT?

A JSON Web Token (JWT) is a compact, signed token used to transmit claims between two parties — most commonly between a client and a server in authentication flows. When you log in to a web application, the server often issues a JWT that your browser sends with every subsequent API request. The server verifies the token's signature without needing to query a database for session state.

A JWT has three parts, separated by dots:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ1c2VyXzEyMyIsInJvbGUiOiJhZG1pbiJ9.SflKxwRJSMeKKF2QT4fwpMeJf36P
Header
algorithm & type
Payload
claims & user data
Signature
integrity proof

Standard JWT claims reference

subSubject — who the token is about (usually a user ID)
issIssuer — which service created the token
audAudience — which service(s) should accept it
expExpiry — Unix timestamp after which the token is invalid
iatIssued at — Unix timestamp when the token was created
nbfNot before — token is invalid before this timestamp
jtiJWT ID — unique identifier, used to prevent replay attacks

Any claim not in this list is a custom (private) claim defined by the application issuing the token.

Is it safe to paste a JWT here?

This tool runs entirely in your browser — no data is sent to any server. However, be cautious: JWTs can contain sensitive personal data. Don't paste production tokens with real user data into any online tool. For debugging, use test tokens with fake data.

Frequently Asked Questions