JWT Decoder

Inspect and debug JSON Web Tokens instantly.

Privacy First: Your token is decoded entirely in your browser using local JavaScript. We never store or transmit your tokens to any server.

Header

ALGORITHM & TYPE 
{}

Payload

DATA & CLAIMS 
{}

Signature

HMACSHA256

The signature is used to verify the sender of the JWT and to ensure that the message wasn't changed along the way.

How To Use JWT Decoder?

1

Paste Your Token

Copy your encoded JWT from your application's network logs or authorization header and paste it into the input area.

2

Inspect JSON Parts

The tool instantly breaks the token into its three fundamental parts: Header (Algorithm), Payload (Data), and Signature.

3

Verify Claims

Check the payload for standard claims like 'exp' (expiration) and 'sub' (subject) to ensure your auth flow is valid.

Key Features

Client-Side Secure

Unlike many online tools, our decoder performs all logic locally. Your sensitive auth tokens never touch our network.

Prism.js Syntax

Decoded JSON is rendered with professional syntax highlighting, making it easy to read nested objects and arrays.

Live Updates

No 'Submit' button required. The tool updates as you type, providing immediate feedback on token validity.

Frequently Asked Questions

What is a JWT?
JSON Web Token (JWT) is an open standard that defines a compact and self-contained way for securely transmitting information between parties as a JSON object.
Can this tool crack my token?
No. This tool decodes the Base64 representation. It does not "crack" the signature or guess the secret key. If a token is encrypted (JWE), this tool cannot read it.
Is it safe to use online decoders?
Only if they work entirely in the client-side like this one. Avoid decoders that send your token to a backend for processing.