Auth Tool
JWT Decoder
Decode JWT header and payload locally in your browser.
JWT Decoder
Decoded locally in your browser. Nothing is sent to a server.
Header
Payload
Signature
Overview
Inspect token claims fast during auth debugging, especially when checking issuer, audience, expiration, and subject values.
Examples
Decode standard auth token
Input
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0IiwibmFtZSI6IkpvaG4ifQ.signatureOutput
{"sub":"1234","name":"John"}Invalid token format
Input
abc.defOutput
Error: expected 3 dot-separated token parts.Use cases
- Debug token-based API authentication flows.
- Inspect exp, iss, aud, and sub claims quickly.
- Verify token structure before backend validation.
FAQ
Does this tool verify signatures?
No. It decodes token content only.
Is token data sent to your server?
No. Decoding runs locally in your browser.
Why do I get an invalid token error?
The token must contain exactly three base64url parts.
Can I copy decoded payloads?
Yes. Header and payload can be copied directly.