HMAC Generator

Hash-based Message Authentication Code calculator using Web Crypto API.

Generate Key-Hashed Message Authentication Codes (HMAC) to sign API requests.

Why This Tool Exists

Many APIs (Stripe, AWS, etc.) require you to sign requests using a secret key and a hash function (HMAC-SHA256). This tool lets you regenerate those signatures to debug failed requests.
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My webhook integration was failing signature verification. I used this to verify my manual math against the standard.

Key Capabilities

Core features that make this tool powerful.

SHA-256, SHA-512

Hex/Base64 Output

How It Works

Understanding the processing logic.

Combines a Key and a Message using SHA functions.

Accuracy & Reliability

RFC 2104 standard.

Who Is This For?

API Devs

Debugging webhooks.

Common Mysteries & Fixes

Whitespace

Commonly, a trailing newline in the message changes the hash entirely.

Real-World Scenarios

Webhooks

Verifying signatures.

Why Choose PrivaQuickTools

FeaturePrivaQuickToolsOthers
SecurityLocalServer

Privacy & Security Guaranteed

We do not store, view, or upload your files. All processing happens in your browser's memory. When you close the tab, all data is wiped from memory.

Good to Know

Large files depends on your device RAM. Processing massive video/PDFs may be slower on mobile devices.

Benefits

  • TestableDebug logic errors.

When Not To Use

While we aim for perfection, browser-based tools have limits. This tool might not be the best fit for:

  • Extremely large files (e.g., video over 2GB)
  • Batch processing thousands of files at once
  • Workflows requiring server-side collaboration or cloud storage

Frequently Asked Questions

Common questions about this tool.

Yes, processed locally.