JSON Web Token (JWT) Decoder
Decode and inspect JSON Web Tokens (JWT) headers and payloads 100% privately in your browser without transmitting sensitive tokens.
// Header will appear here
// Payload will appear here
100% Client-Side Privacy
All computation happens right in your browser's JavaScript engine. No data is ever sent to any remote server.
Instant Results
Zero network latency. Calculations and formatting are executed instantly with high cryptographic and mathematical precision.
Works Offline
Once loaded, this tool can function completely offline with no active internet connection required.
Frequently Asked Questions
Is it safe to paste private auth tokens here?
Yes! Decoding occurs 100% locally in your browser. Tokens are never uploaded to any remote server or logged.
Can this tool verify the cryptographic signature?
Signature verification requires a private server secret or public key; this tool is designed for decoding and inspecting token claims.