JWT Decoder
Decode and inspect JWT (JSON Web Tokens). View the header, payload and verify expiration. Processed 100% in the browser — the token never leaves your device.
What is a JWT?
A JSON Web Token (JWT) is an open standard, described in RFC 7519, that carries information between parties as a compact JSON object. It breaks into three parts separated by dots: the Header, which holds the algorithm, the Payload, with the data, and the Signature, which is the signature. Keep in mind that, by default, the token isn't encrypted. It's only encoded in Base64URL.
Decode and inspect JWT tokens
The JWT (JSON Web Token) shows up in nearly every API authentication, yet that long Base64-encoded string reveals nothing at a glance. This decoder opens the token and lays out its contents in a readable form, splitting the header from the payload so you see exactly what sits inside.
Beyond showing the claims, it reads the time fields and flags whether the token has already expired. That's precisely what you need when debugging a failing login or a rejected request. The header's algorithm, the payload data and the validity all appear, neatly organised, instead of you decoding Base64 by hand.
Processing is 100% in the browser, so the token never leaves your device or reaches any server. One thing worth remembering: decoding isn't verifying the signature. Anyone can read a JWT's contents, so never store secrets inside one.
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