JWT Decoder
Decode JSON Web Tokens to inspect header, payload, and signature. Free, instant, 100% private — no data leaves your browser.
About JWT Decoder
JWT (JSON Web Token) is the standard for secure API authentication and information exchange. Our decoder lets you inspect any JWT:
- Header: Contains the signing algorithm (HS256, RS256, etc.) and token type
- Payload: Contains the claims — user ID, expiration, issuer, custom data
- Signature: Verifies the token hasn't been tampered with (requires secret key to verify)
Common Claims
| Claim | Meaning |
|---|---|
sub | Subject — typically the user ID |
iat | Issued At — when the token was created |
exp | Expiration — when the token expires |
iss | Issuer — who created the token |
aud | Audience — who the token is intended for |
🔒 All decoding happens in your browser. Tokens never leave your device.
About JWT Decoder
Decode and inspect JSON Web Tokens (JWT). View header, payload, and signature. Validate token expiration, issuer, and claims. Developer tool for debugging authentication and API integrations. All in your browser.
Header & Payload View
Decodes all three JWT parts. View algorithm type, token claims, expiration, issuer, and custom fields.
Expiration Check
Automatically checks exp claim and shows if token is expired. Color-coded valid/expired indicator.
Pretty-Printed JSON
Formatted JSON output for both header and payload. Easy to read, copy, and inspect claims.
Secure & Local
JWT decoded locally in your browser. Tokens never sent to any server — safe for production credentials.