JWT Decoder

Decode and inspect JSON Web Tokens. View header, payload, and check expiration status.

JWT StructureA JWT has three Base64URL-encoded parts separated by dots: header.payload.signature

Header

Algorithm & type

Payload

Claims & data

Signature

Verification hash

Paste a JWT token above to decode it

Or try one of the example tokens

How to Use the JWT Decoder

1

Paste Your Token

Copy a JWT token from your application, API response, or browser cookies and paste it into the input field.

2

View Decoded Data

The header and payload are decoded and displayed with syntax highlighting. Check the algorithm, claims, and timestamps.

3

Check Expiration

If the token has an 'exp' claim, you'll see whether it's expired or still valid, with the exact expiration date.

Features

Decode JWT header and payload instantly
Syntax-highlighted JSON output
Automatic expiration status checking
Shows algorithm and token type badges
Supports all JWT signing algorithms (HS256, RS256, ES256, etc.)
Copy decoded header or payload with one click
Works entirely in your browser — tokens never leave your device
Free to use with no sign-up required

Frequently Asked Questions

No. This tool decodes and displays the token contents. Signature verification requires the secret key or public key, which should never be shared with online tools.

Yes. The token is decoded entirely in your browser using JavaScript's atob() function. Nothing is sent to any server. However, avoid sharing tokens publicly.

The 'exp' (expiration) claim is a Unix timestamp indicating when the token expires. After this time, the token should no longer be accepted by servers.

'sub' is the subject (usually user ID), 'iat' is issued-at timestamp, 'exp' is expiration, 'iss' is the issuer, 'aud' is the audience, and 'nbf' is not-before timestamp.

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