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JWT Signature & HMAC-SHA256 Secret Verifier

Verify JSON Web Token signatures with your HMAC-SHA256 secret key locally in your browser using the Web Crypto API.

Paste JWT Token (Encoded)
HMAC-SHA256 Secret Key
Decoded Payload

    






        


        
        
        

            
Frequently Asked Questions

            

                
                

                    
Is my secret key sent to any server?

                    
NO. Verification uses the native browser Web Crypto API (SubtleCrypto)β€”zero data leaves your device.

                

                
                

                    
What algorithm is supported?

                    
Supports standard HS256 (HMAC with SHA-256) signature verification.

                

                
                

                    
Does it decode the payload?

                    
Yes, the payload JSON is automatically decoded and formatted alongside the verification check.

                

                
            

        

        

        
        
        

            
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Embed this Tool on Your Site

                
            

            

                Copy and paste this snippet into your blog, documentation, or tech site to embed this interactive utility: