Local HS256 test JWT generator
Create an HS256-signed test JWT from your own JSON claims and secret to try out an API or login flow; not for production use.
- Runs in your browser
- No upload
- Result stays on your device
Privacy & limitsRuns in your browser. Nothing is uploaded.
Input content stays in this tab; Refentra does not upload or store it. Optional aggregate action counts are sent only with your usage consent. Clear the workspace when finished.
Supported profile: HS256 test tokens only; test secret ≥32 UTF-8 bytes. No production-authentication promise.
Maximum text: 200,000 UTF-16 units; parser limits can be smaller. Worker time limit: 15 seconds (regex 1.5 seconds).
Check the input and the result
- Prepare and choose the operation
Enter a JSON object payload and a test secret of at least 32 UTF-8 bytes. Tokens are generated with HS256.
- Check a concrete example
Use this sample and compare the indicated result: {"sub":"demo"}; secret=0123456789abcdef0123456789abcdef → HS256 JWT → payload.sub="demo"
- Check the output before you reuse it
Decode your test token to check the claims, then verify its signature separately in the receiving application, using the same secret.
Answers for this task
Does the generator grant authentication?
No. The receiving service decides which algorithm, issuer, audience, expiry and keys are acceptable. Signing alone grants no permissions.
What should I check if the input fails?
Use an object, not an array. The payload can be up to 20,000 UTF-16 units and the secret up to 4,096. Byte length is not the same as character count.
Where does this tool stop?
Only HS256 test signing is provided. There are no asymmetric keys, key rotation or secure server-side secret management. Never reuse the published example secret.