JWT Tools

JWT Validator

JWT Validator checks a JWT structure and exp, nbf, and iat claims, and can verify the HS256 signature with your secret. Free, fast, and completely private.

Client-sideRuns entirely in your browser — your data never leaves your device.

JWT Validator is a free JWT Tools utility that runs entirely in your browser — nothing you enter is uploaded.

JWT
Validation report



  
How to use JWT Validator

  
    
      
  1. Paste the JWT you need to validate into the input box.
    2. 
      
  2. Set HMAC secret (optional, HS256) so the output fits your use case.
    3. 
      
  3. Press Validate and JWT Validator shows the result straight away.
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  4. Finish by choosing Copy to take the output with you.
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About this tool

  
There is no server behind JWT Validator. JWT Validator splits and base64url-decodes a JWT locally so you can inspect its claims.

  
Signature verification that needs a secret should be done in a trusted environment; JWT Validator focuses on decoding. It behaves the same on desktop and mobile, with nothing stored remotely.

  
Frequently asked questions

  

      
What does JWT Validator do?
Use JWT Validator to validate your input without installing anything using the HMAC secret (optional, HS256) control; everything happens client-side.

      
Is JWT Validator free to use?
Yes — JWT Validator is completely free, with no usage limits.

      
Is my input private in JWT Validator?
Yes — your input never leaves your device; JWT Validator does all the work in your browser.

      
Does JWT Validator verify the JWT signature?
JWT Validator decodes the token locally so you can inspect its header and payload; verification needs the matching key.

      
Does JWT Validator work offline?
Once the page has loaded, JWT Validator keeps working with no network connection.

  

  
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