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JWT Encoder (Create & Sign HS256)

Create a signed JSON Web Token from a payload and secret (HS256/384/512) for testing APIs.

Tool inputs stay in your browser · optional AI search sends your query

Good to know: A JWT is a login “pass” made of header.payload.signature. The secret signs it so the server knows it was not changed. Use test secrets only; signing happens in your browser.

How to use it (step by step)

  1. 1Type or paste your text into the “Payload (JSON)” box. There is already an example in it so you can see how it works; press Clear to start with your own.
  2. 2Choose your settings: “Secret key (test only)”, “Algorithm”, “Add “issued at” (iat)”, “Expires in (exp)”.
  3. 3The answer appears right away in the “Signed JWT” box. No button needed.
  4. 4Press Copy and paste the result wherever you need it.

Words to know

JSON
A common text format apps use to store and send data, made of names and values in { } brackets.
JWT
A login “ticket” websites give you, written as three parts separated by dots.
App signing / keystore
Every app is signed with a private key (kept in a keystore file). Updates must be signed with the same key, so never lose it.
HMAC / signature
A secret code made from the message and a secret key. If the code matches, you know the message is real and was not changed.

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