JWT Analyzer
Decode and analyze JSON Web Tokens (JWT). View the header, payload, and signature parts, along with token claims and validity information.
Why use this tool?
JWTs are widely used for authentication and authorization in modern web applications. This tool helps developers quickly inspect token contents without needing backend access.
- Instant decoding — see header, payload, and signature immediately.
- Claim analysis — view standard claims like exp, iat, iss, and custom claims.
- Validity check — know at a glance if the token is expired.
- Private — all processing happens in your browser. Nothing is uploaded.
- Educational — understand JWT structure and claims.
How to use
- Paste your JWT token into the input field.
- Click Analyze Token to decode it.
- View the decoded header, payload, and signature in separate panels.
- Check the token information section for claim details and expiration status.
- Use the copy buttons to copy individual parts.
Frequently Asked Questions
A JSON Web Token (JWT) is a compact, URL-safe means of representing claims to be transferred between two parties. It consists of three parts: a header, a payload, and a signature.
All decoding happens entirely in your browser. Your token is never sent to any server. However, avoid pasting tokens with sensitive data like passwords or private keys.
No. This tool only decodes and displays the token contents. Signature verification requires the secret key, which should never be entered in a web tool.
The tool displays all standard claims (iss, sub, aud, exp, nbf, iat, jti) and any custom claims present in the token payload.