Read the token. Trust the signature.

Two tools for JSON Web Tokens — a decoder that shows every claim and checks the signature against a key you supply, and an encoder that builds and signs a fresh token. Signing runs on WebCrypto in this tab, so the secret you paste is never transmitted.

Choose a tool

2 tools · more coming

JWT Decoder

Read a token’s claims, and prove its signature.

Header and payload
Expiry in plain words
Signature check
Secret or public key

Open

JWT Encoder

Build a token from claims, and really sign it.

Header and payload
HS / RS / PS / ES
Expiry presets
Signs with WebCrypto

Open

Nothing you paste is uploaded

Every tool here is JavaScript running in your own tab. Paste a production payload with the network disconnected and it still works — there is no server of ours that could receive it.

No ads, no account, no limit

No interstitials, no sign-up and no cap on how much you can paste. The page you land on is the tool.

Your key never leaves the tab

Signing and verification run on WebCrypto, the browser’s own primitive. The key is held in memory, used, and dropped — it is the one input on this site that is deliberately not saved.

Check the claim in your Network panel.

How that is true