About JWT Decoder

Paste any JSON Web Token and instantly decode its header and payload — no key required. See the algorithm, token type, issued-at and expiration timestamps (converted to human-readable dates), issuer, subject, and all custom claims in a formatted JSON view. Essential for debugging authentication flows, verifying token contents during API development, and checking token expiry before troubleshooting session issues.

How to Use JWT Decoder

1. 1Paste a JWT token string into the input field
2. 2The header and payload are decoded and displayed instantly
3. 3Check the expiration time, issuer, subject, and custom claims
4. 4Verify the signature status — the tool shows whether the token is expired

When to Use JWT Decoder

• ▸Inspecting JWT tokens from API responses and browser storage
• ▸Debugging authentication issues by reading token payloads
• ▸Verifying token expiration times before they expire
• ▸Learning about JWT structure in development and training

Frequently Asked Questions

Does it verify the JWT signature?

The tool decodes the header and payload (which are base64-encoded, not encrypted) and checks expiration. Full signature verification requires the secret key or public key, which is not supported in this client-side tool for security reasons.

Is my JWT token secure while decoding?

All decoding happens locally in your browser. The token is never sent to any server. However, JWTs can contain sensitive data — be careful where you paste them.