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HMAC Generator & Verifier

The recommended key length corresponds to the length of the Hash output: SHA-1=20 bytes, SHA-256=32 bytes, SHA-384=48 bytes, SHA-512=64 bytes

Notes

  • • HMAC Generates signatures based on key and Hashi algorithms for authentication of source and integrity
  • • Support SHA-1 / SHA-256 / SHA-384 / SHA-512
  • • Generate and validate both locally in browsers, without uploading data
  • • Validation uses fixed length by bytes to reduce time series differences

Free online HMAC signature generator and verifier supporting common SHA algorithms. Perfect for API signatures, Webhook verification and security debugging.

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Use Cases

  • Generate HMAC signatures for API request authentication
  • Verify Webhook callback message signature validity
  • Troubleshoot API signature inconsistency issues and confirm keys and algorithms
  • Debug signature mechanisms for open platforms or payment APIs

Features

  • Signature generation and verification: ideal for API integration, Webhook callbacks and message authentication
  • Common algorithm support: HMAC-SHA1, SHA256, SHA512 and other popular signature workflows
  • Signature mismatch troubleshooting: quickly verify key, message and algorithm matching
  • Easy to copy: sync results with backend, testing or integration documentation

How to Use

  1. 1.Select the HMAC algorithm (e.g., HMAC-SHA256)
  2. 2.Enter the message and secret key
  3. 3.The tool automatically generates the HMAC signature
  4. 4.Copy the signature for API requests or compare with expected signature

FAQ

What is HMAC used for?

HMAC is commonly used for API signatures, Webhook verification, callback validation and message integrity protection. It is a standard mechanism in many open platforms and server communications.

Is it useful for API signature and callback verification debugging?

Absolutely. Whether for payment callbacks, Webhooks, open platform signatures or internal API integration, HMAC result verification is frequently needed.

What is the difference between HMAC and regular hashing?

HMAC adds a key on top of hashing, making it suitable for message authentication and signature verification. Regular hashing is more for digests and integrity checks.

Can it help locate signature inconsistency issues?

Yes. Many signature errors relate to mismatched keys, messages, encoding formats or algorithms. A dedicated tool is ideal for quick cross-verification.