JWT Signature Verifier
JWT Signature Verifier is a free online Security Tools tool that decode a JWT and verify its HS256 signature locally, with exp/nbf/iat claim checks instantly in your browser. Paste your data, adjust the options and get the result in real time — no installation, no sign-up, and nothing is ever uploaded to a server.
How to use: JWT Signature Verifier →
Description
Decode a JWT and verify its HS256 signature locally, with exp/nbf/iat claim checks.
- Because everything is computed client-side, JWT Signature Verifier is safe to use with sensitive data such as API keys, tokens or private logs.
How to use
Using JWT Signature Verifier takes three steps:
- Paste your data into the input box (or load the example).
- Configure the options to match your target format or scenario.
- Copy, download or inspect the output — it updates live as you type.
Examples
These ready-made examples show typical inputs and the exact output JWT Signature Verifier produces for them.
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5c
Enter your-256-bit-secret in the secret field to see the signature verify; any other secret is rejected.
Use cases
Common situations where JWT Signature Verifier helps:
- Decode a JWT and verify its HS256 signature locally, with exp/nbf/iat claim checks.
- Because everything is computed client-side, JWT Signature Verifier is safe to use with sensitive data such as API keys, tokens or private logs.
FAQ
What is JWT Signature Verifier?
JWT Signature Verifier decode a JWT and verify its HS256 signature locally, with exp/nbf/iat claim checks. It runs entirely in your browser, so your data stays private.
Is JWT Signature Verifier free to use?
Yes. JWT Signature Verifier is free, unlimited and works without registration or installation.
Does my data get uploaded?
No. All processing happens locally in your browser; nothing is sent to any server.