JWT Decoder & ValidatorFree Tool

Yes, absolutely! All JWT decoding happens locally in your browser using JavaScript. No tokens are sent to our servers or stored anywhere. Your data never leaves your device, making it completely safe for production tokens.

This usually happens because you haven't provided the correct secret key or public key for verification. The token structure is valid, but signature verification requires the exact key used to sign the token. If you don't have the key, you can still view the decoded header and payload.

The security score (0-100) evaluates your JWT based on industry best practices. It considers factors like algorithm strength, expiration settings, sensitive data exposure, and compliance with security guidelines. A score above 80 is excellent, 60-80 is good, and below 60 needs improvement.

Yes! Our decoder supports all standard JWT algorithms including HS256, HS384, HS512, RS256, RS384, RS512, ES256, ES384, ES512, PS256, PS384, and PS512. You can decode any valid JWT regardless of the algorithm used.

JWT timestamps are typically in Unix epoch format (seconds since Jan 1, 1970). If times appear incorrect, verify that your token's 'iat', 'exp', and 'nbf' claims are in the correct format. Our tool automatically converts these to human-readable dates in your local timezone.

JWTs are encoded but not encrypted - anyone can decode them. Remove sensitive information like passwords, social security numbers, or private data from the payload. Instead, store only non-sensitive identifiers and use these to look up sensitive data server-side.