JWT Decoder
Decode JSON Web Tokens into readable header and payload, for free.
This tool runs entirely in your browser. Your files are never uploaded to a server.
Paste a JWT (JSON Web Token) to instantly see its decoded header and payload as readable JSON. This tool only decodes and inspects tokens — it does not verify signatures. Because a JWT can contain sensitive claims like user IDs or permissions, everything runs entirely client-side: your token is decoded right in your browser and never leaves your device or gets sent to any server.
Frequently Asked Questions
- What does this tool do?
- It decodes a JWT's header and payload into readable JSON so you can inspect its claims. It does not verify the signature — it's purely a decoding and inspection tool.
- Is my token safe to paste here?
- Yes. The entire decoding process happens locally in your browser using JavaScript — your token is never uploaded or sent to any server, which matters since JWTs often contain sensitive claims.
- Why can't I see if the token is valid?
- Validating a signature requires the secret key or public key used to sign the token, which this tool never asks for or has access to. It only decodes the readable parts of the token.