SHA-256 Hash Generator

Your text is converted to UTF-8 bytes and passed to the browser's Web Crypto function crypto.subtle.digest("SHA-256"). The digest is shown as 64 lowercase hex characters and recalculates on each keystroke.

To check the page against your own machine, run printf hello | sha256sum on Linux, printf hello | shasum -a 256 on macOS, or in PowerShell Get-FileHash on a file that contains only those five letters.

SHA-256 works on exact bytes, not on meaning. Two JSON documents that a parser treats as equal can hash differently:

• {"a":1,"b":2} gives 43258cff…
• {"b":2,"a":1} gives 3fb75453…
• The first object pretty-printed with two-space indents gives c81ded0f…

If two services need to agree on a hash of the same data, they must agree on the exact serialisation first: key order, spacing, number format and line endings. When you're debugging a mismatch, copy the exact string each side hashed from its logs and paste each one here, rather than re-typing the data.

• Webhook and API signatures: these are usually HMAC-SHA256, which mixes a secret key into the calculation. A plain SHA-256 of the payload, which is what this page produces, will never match an HMAC signature, even with the right payload.
• Base64 instead of hex: some formats, including subresource integrity attributes, expect the digest in Base64. hello in Base64 form is LPJNul+wow4m6DsqxbninhsWHlwfp0JecwQzYpOLmCQ=. This page shows hex only, so convert the bytes with a tool or a line of code, not by Base64-encoding the hex text.
• Files: the box takes text. For a downloaded file's checksum, run the command-line tools above on the file itself.