JWT Decoder - Decode JSON Web Tokens & Check Expiry Online
Instantly decode JSON Web Tokens (JWT) into readable Header, Payload, and Signature components with automated expiry checking.
This tool runs in your browser.
Your result will appear here.
How to use
- 01Paste your encoded JSON Web Token (xxx.yyy.zzz) into the editor.
- 02The decoder separates and parses Header, Payload claims, and Signature details.
- 03Inspect token expiration status and copy decoded JSON blocks with one click.
FAQ
Is it safe to paste private authentication tokens here?
Yes. Decoding uses client-side Base64URL string parsing inside your browser. No token data is ever transmitted across the internet.
Why can JWTs be read without needing the secret key?
JWT headers and payloads are Base64URL-encoded rather than encrypted. Secrets are solely required to verify the digital signature.
How does the tool alert me about expired tokens?
It parses standard "exp" and "iat" claims and compares them with current UTC time, clearly displaying remaining validity or expiration.