JWT Decoder & Inspector
Decode JSON Web Tokens instantly. Inspect header properties, payload claims, expiration flags, and signatures entirely client-side.
Encoded Token Input
Header: Alg & Token Type
// Decoded header will appear here...
Payload: Data & Claims
// Decoded payload claims will appear here...
Signature Verification
HMAC / RSA// Signature hash will appear here...
About JSON Web Tokens (JWT)
Learn how compact, URL-safe authentication tokens work across microservices and web APIs.
A JSON Web Token (JWT) is an open industry standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. Because they are digitally signed using a secret (with HMAC) or a public/private key pair (with RSA or ECDSA), the information can be trusted and verified instantly.
Real-Time Inspection
Decodes headers and payload claims instantly character-by-character as you paste or modify tokens.
Expiration & Time Tracking
Automatically identifies `exp`, `nbf`, and `iat` numeric timestamps, converting them into clear human-readable local dates.
100% Client-Side Secure
No network requests or backend telemetry. Your session tokens, API keys, and sensitive user claims never leave your device.
Three-Part Breakdown
Cleanly separates the encoded string into distinct color-coded blocks for headers, payloads, and cryptographic signatures.
Sample Presets Included
Instantly load valid, expired, or custom-claim sample tokens to test inspection features right away.
One-Click Copy Blocks
Quickly copy formatted JSON headers or payloads directly to your clipboard for debugging and testing.