SHA-256 Hash Generator

Creating secure hashes and HMAC signatures

The SHA-2 family of hash functions is the modern standard for creating fingerprints of data. This tool calculates SHA-256, SHA-384 and SHA-512, along with the older SHA-1, from the same input at once, so you can copy whichever one a system expects. Developers use these hashes to verify file downloads, generate cache keys, compare records and check that data has not been altered.

Add a secret key and the tool produces HMAC values instead of plain hashes. HMAC combines the message with the key, so only someone who knows the key can produce the same result. That is how many payment gateways, webhook providers and APIs sign their requests. When your server receives a webhook, it calculates the HMAC of the body with the shared secret and compares it with the signature sent in the headers. This tool helps you check your implementation by producing the expected value for a sample payload.

A few points prevent common mistakes. The exact bytes matter, so extra spaces, line breaks or different JSON formatting will produce a different hash. When verifying webhooks, hash the raw request body exactly as received, not a re-formatted version. SHA-1 is included for older systems, but it is no longer considered safe for signatures, so prefer SHA-256 for new work. For storing passwords, even SHA-256 is too fast; use a slow, salted algorithm such as bcrypt or Argon2. All calculations use your browser's built-in cryptography and nothing is sent anywhere, so it is safe to test with real secrets on your own machine.