ADVERT

🔏 HMAC Generator

Compute HMAC signatures with SHA-256, SHA-1, or MD5 using a secret key. Secure online hashing tool.

HMAC Generator

Generate HMAC signatures using SHA-1, SHA-256, SHA-384, or SHA-512. Provide a secret key and message to calculate the signature. Useful for developers, security testing, and verifying message integrity.

Message

HMAC (SHA-256)

How to use this tool

Select the hashing algorithm and enter your shared secret key.
Provide the message payload—JSON, webhook content, or any text you need to sign.
Copy or download the resulting HMAC to compare with the signature from your API partner.

Common tasks

Debug webhook verifications by regenerating signatures locally.
Validate SDK implementations when onboarding new integrations.
Teach junior developers the difference between hashing and keyed message authentication.

Security tips

Keep secrets short-lived and rotate them regularly—the tool never stores your inputs.
Match the algorithm to what your service expects; mismatched digests will never verify.
Normalize whitespace and encoding (UTF-8) before signing to avoid subtle mismatches.

FAQ

Why can’t I use MD5?: The Web Crypto API focuses on modern SHA algorithms. Most providers no longer accept MD5-based HMACs.
Does the tool send my secret anywhere?: No. All calculations happen in your browser using the built-in SubtleCrypto interface.
How do I verify a signature?: Generate an HMAC using the same inputs and compare the hex digest to the signature supplied with the request. Identical values confirm authenticity.

ADVERT

More like this

Format YAML, convert between YAML and JSON, and validate syntax instantly in your browser with offline support.

Decode JWT header and payload safely in your browser. Inspect claims and structure without sending tokens anywhere.

Create signed JSON Web Tokens with customizable headers and payloads. Choose HS256, HS384, or HS512 HMAC algorithms and copy the ready-to-use JWT.

Visually craft cron expressions with presets, interval selectors, and quick toggles. Copy the expression and preview the next scheduled runs instantly.

Parse cron expressions and preview next run times. Useful for devs managing scheduled tasks and crontab jobs.

Test and debug JavaScript regular expressions. Highlight matches and quickly verify regex patterns.

Compose regular expressions with guided toggles for character sets, anchors, quantifiers, and flags. Test against sample input instantly.

Parse a URL into protocol, host, path, query string, and hash. Quick online URL analyzer tool.

ADVERT