JWT Signer (HS256 / HS384 / HS512)
Build and sign a JWT with an HMAC secret — all in your browser.
Set header and payload as JSON, paste your HMAC secret, get a signed JWT. Pairs with our JWT decoder so you can round-trip and verify.
Pair with our JWT decoder to round-trip and verify.
Runs entirely in your browser — nothing you enter is sent to a server.
Need this for real, on your stack?
These free tools are a taste of how we think. We’re a senior software team across Romania & Pakistan that ships deep technical work — platforms, infra, data and the gnarly bits in between.
Talk to our engineers →Privacy
Everything runs in your browser via Web Crypto — secrets never leave the page. As always, never test with production keys: rotate anything you paste anywhere online.
Algorithm choice
HS256 is fine for service-to-service tokens with a shared secret. For tokens that traverse trust boundaries, use RS256/ES256 and keep your private key on one side.
Built by WeWorkWorldwide — a senior software team in Romania & Pakistan that ships deep technical work. Need this turned into something production-grade for your stack? Talk to our engineers →