JWT Decoder

Paste a JWT and instantly see its header, payload and signature details — decoded locally in your browser.

Your token is decoded locally in your browser and never sent anywhere.

How to use JWT Decoder

  1. Paste the JWT (the long base64 string, usually starting with eyJ…).
  2. The header and payload are decoded and formatted automatically.
  3. Review the claims and copy what you need.

About this tool

JSON Web Tokens pack information — like user IDs and expiry times — into a compact, signed string. This tool decodes the two readable parts (the header and the payload) so you can inspect claims during development and debugging.

Important: decoding does not verify the signature. Anyone can read a JWT’s contents without the secret, so tokens should never carry sensitive data.

When to use it: debugging logins and APIs that pass tokens around.

Frequently asked questions

Does this verify the token’s signature?
No. This tool only decodes the header and payload. It does not validate the signature or check expiry, so treat the contents as untrusted until verified server-side.
Is it safe to paste a JWT here?
The token is decoded entirely in your browser and never transmitted. Even so, avoid pasting tokens that contain secrets or that grant access to live systems.
What do the exp and iat claims mean?
exp is the expiry time and iat the issue time, both as Unix timestamps — paste them into the Timestamp Converter to read them as dates.
Why does a JWT have three parts?
Header, payload and signature. The first two are readable Base64; the third is the cryptographic seal, which this tool deliberately does not verify.
Can I edit a token here?
No — this is a reader, not a signer. Any change to the payload would invalidate the signature anyway.
Does token length matter?
Yes — the token travels with every request, so lean payloads keep traffic small. Store large data server-side and reference it by ID.

Related tools

Base64 Decoder Decode Base64 text back to readable text or a file. JSON Formatter Format, indent and beautify JSON data so it is easy to read. Timestamp Converter Convert Unix timestamps to dates and dates to timestamps.

Browse all Developer Tools →

How to use Jwt Decoder

Paste your code, data, or URL into the Jwt Decoder input area. Select the appropriate mode or option, then process. The formatted or converted output appears clearly and can be copied or saved.

Practical benefits

Frequently asked questions

Is this tool free to use?
Yes. Jwt Decoder is fully free with no account or subscription required.
Does it upload my files?
No. All processing occurs locally within your browser session.
Can I use this for professional projects?
Yes, the tool is designed for both casual and professional use. Always verify critical outputs.