JWT Validator

JWT Validator & Signature Verification

A JSON Web Token (JWT) is only secure if its cryptographic signature is valid. Our JWT Validator lets you paste any JWT alongside its secret or public key to verify that the token has not been tampered with and is cryptographically secure.

Zero Data Tracking: All cryptographic validations are performed securely inside your browser using the Web Crypto API. We never log or transmit your tokens or secrets.

Core Features

• Local Signature VerificationSupport for verifying HS256, HS384, HS512, RS256, RS384, RS512, ES256, ES384, and ES512 signatures without server calls.
• Expiration ChecksAutomatically checks the exp (Expiration Time) and nbf (Not Before) claims to ensure the token is currently active.
• Detailed Error ReportingPinpoints exactly why a token failed validation—whether it's an invalid signature, expired token, or malformed structure.