Decode and understand any JSON Web Token in your browser — every header and claim explained, human-readable timestamps with a live expiry countdown, HS256 signature verification, and a plain-English security analysis (alg:none, RS256, expiry). A teaching tool, not just a decoder. Nothing is ever uploaded.
Where it runs
Your browser
Data retention
None — nothing is uploaded or stored
Maintained by
EasyTechLabs Engineering
🔒 Your token and any secret you enter to verify it are processed entirely in your browser and are never uploaded, stored, or logged. A JWT often contains identity data — decoding it here keeps it on your device.
The token's three Base64url segments (header.payload.signature) are decoded to JSON in your browser. Each registered claim is explained, and the exp/nbf/iat timestamps are shown as human-readable dates with a live expiry countdown. For HS256 tokens you can paste the shared secret to verify the signature locally with the Web Crypto API (HMAC-SHA256). Decoding never verifies a signature — the tool states this plainly, flags alg:"none" as unsigned, and explains why RS256/ES256 tokens need the issuer's public key.
A JWT has three Base64url parts separated by dots: header.payload.signature. Paste one (or load the sample) to decode every field, see human-readable timestamps and expiry, verify an HS256 signature, and read a plain-English security analysis. Decoding happens entirely in your browser — the token is never uploaded.
🔒 Runs entirely in your browser — nothing you paste, type, or drop is uploaded, stored, or logged.