JWT Decoder

A JWT Decoder lets you instantly parse and inspect JSON Web Tokens — the compact, URL-safe tokens widely used for authentication and authorization in modern web applications. By splitting the token into its three parts — header, payload, and signature — you can read the encoded data in plain, human-readable JSON, making it easy to understand exactly what information a token carries and how it was signed.

This tool is invaluable for developers working with APIs, OAuth flows, OpenID Connect, or any system that issues JWTs. Instead of writing custom decoding logic or hunting through documentation, you can paste a token and immediately verify claims, check expiration times, confirm the algorithm used, and debug auth issues on the spot.

Using the JWT Decoder is straightforward. Paste your JWT — a three-part string separated by dots (e.g. xxxxx.yyyyy.zzzzz) — into the input field and the tool will instantly split and base64url-decode each segment. The header section will reveal metadata such as the token type and signing algorithm (e.g. HS256, RS256). The payload section exposes all claims, including standard ones like sub, iat, exp, and aud, as well as any custom claims your application has added.

The output is presented as formatted, syntax-highlighted JSON for each section, making it easy to scan and share. Expiration (exp) and issued-at (iat) timestamps are automatically converted to human-readable dates so you can tell at a glance whether a token is still valid or has already expired.

Keep in mind that decoding a JWT does not verify its signature — it only reads the raw data. Signature verification requires the secret or public key and must be done server-side. Never use decoded JWT data from an untrusted source as a basis for access decisions without proper validation. Also note that some JWTs are encrypted (JWE) rather than just signed (JWS); encrypted tokens will not be readable through a standard decoder.