JWT Decoder
Use this JWT decoder to inspect a token's header and payload without sending it anywhere. It decodes Base64URL segments and shows common metadata such as timestamps.
Example Usage
- Paste a JWT to inspect header fields such as alg and typ.
- Read payload claims like sub, exp, and iat while debugging auth flows.
- Check whether a token has a signature section and how long it is.
JWT Decoder Explained
A JWT decoder helps you inspect the readable parts of a JSON Web Token without verifying the signature or calling a backend service. JWTs are commonly used in authentication and API workflows, and they contain a header, a payload, and usually a signature segment. This tool decodes the Base64URL-encoded header and payload in the browser, formats them as JSON, and surfaces common metadata such as issue time or expiration time when present. That makes it convenient for debugging tokens, checking claims, and understanding what a JWT contains during development.
FAQ
Does this tool verify the JWT signature?
No. It decodes the token structure but does not verify the signature.
Can I inspect exp and iat fields?
Yes. Common timestamp claims are displayed in a readable format when present.
Is it safe to use without a backend?
Yes. Decoding happens locally in the browser.
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