JWT Decoder - Free Online Tool | PivaBox

Decode JWT tokens to view header, payload, and signature info

JWT Decoder — Decode and Inspect JSON Web Tokens for Debugging

  1. Paste your JWT token into the input field. A JWT looks like three base64-encoded segments separated by dots: header.payload.signature. The tool accepts standard JWTs, including those with custom claims.
  2. The decoder instantly parses and displays the header (algorithm type, token type) and the payload (claims, user info, permissions, expiration time). The decoded data is formatted as readable JSON with syntax highlighting.
  3. Review the decoded claims — check the issued-at (iat) and expiration (exp) timestamps, verify user roles and permissions, inspect custom claims, and debug authentication issues in your application.

Frequently Asked Questions

Is the JWT Decoder free?

Yes, completely free. Debug as many tokens as you need — ideal for developers troubleshooting authentication flows, API integrations, and SSO implementations.

Are my JWT tokens uploaded anywhere?

No. All decoding happens locally in your browser. Your tokens — which may contain sensitive user data, API credentials, or session information — never leave your device. This is critical for security: you should never paste real production tokens into an online service.

What information is inside a JWT and how do I read the claims?

A JWT (JSON Web Token) contains three parts: (1) Header — specifies the signing algorithm (HS256, RS256, ES256, etc.) and token type. (2) Payload — contains registered claims like iss (issuer), sub (subject), aud (audience), exp (expiration time as Unix timestamp), iat (issued-at time), plus any custom claims your application adds (user ID, roles, permissions, tenant ID). (3) Signature — the cryptographic signature that verifies the token has not been tampered with. This tool decodes the header and payload for inspection; signature verification requires the secret key or public key, which you should keep secure. Use the Unix timestamp converter on our site to translate exp/iat values into human-readable dates.