UtilityKit

JWT Decoder & Validator

Decode, verify, and inspect JSON Web Tokens for security flaws.

Provide the shared secret for HMAC (HS256) tokens to verify the signature status below.

Awaiting Input

Paste a JWT string to decode its header and payload, visualize timestamps, and verify signatures.

Step-by-Step Guide

  1. 1Paste your JSON Web Token (JWT) into the input field.
  2. 2The tool will automatically decode the header and payload sections.
  3. 3Review the decoded claims (like issuer, expiration, and subject) in the output panels.
  4. 4To verify the signature, enter your secret key in the verification section.
  5. 5The tool will confirm if the token signature is valid and if the token has expired.

Why use this tool?

JSON Web Tokens (JWT) are the standard for stateless authentication in modern web applications. Our JWT Decoder allows developers to securely inspect the contents of their tokens, verifying claims and expiration dates. By processing the decoding entirely client-side, it ensures your sensitive authentication tokens are never exposed to external servers.

Privacy Note: Like all tools on UtilityKit, this utility runs entirely in your browser. No data is sent to our servers.