JWT Decoder
Inspect a JSON Web Token's header and payload in your browser.
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Decoding a JWT does not verify its signature. This tool only inspects the header and payload — it never transmits your token anywhere.
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What is the JWT Decoder?
The JWT Decoder inspects a JSON Web Token and displays its decoded header and payload as pretty-printed JSON, along with issued-at and expiration timestamps where present. It is a decoder and inspector only — it does not verify a token's signature.
How to use it
- Paste a JWT into the input box.
- The decoded header and payload appear instantly below.
- Check the issued-at and expiration badges for token timing.
- Copy any section individually using its copy button.
Features
- Decodes JWT header and payload
- Displays the raw signature segment
- Pretty-printed JSON output
- Expiration and issued-at detection
- Per-section copy buttons
- Fully client-side — tokens are never transmitted
Privacy
This tool never sends your token to a server. All decoding happens locally in your browser using the Web Crypto-free Base64URL decoding built into JavaScript.
Frequently Asked Questions
No. Decoding a JWT only reveals its contents — it does not verify the signature, so a decoded token should never be treated as authenticated or trustworthy on its own.
No. Everything happens locally in your browser; the token is never sent to any server.