Signature Calculator

Generate or validate HMAC-SHA256 signatures for Seller API requests. All computation happens in your browser — your secret key is never sent to our servers.

New to signing? Read the signing documentation first. Getting a corrupted-signature error? Fill in Compare against to find out exactly why.

Include the full URL with any query parameters (e.g. ?storefront=de). Signed verbatim — do not re-encode.
0 bytes • • Show whitespace
Included in the signature exactly as entered — encoding, whitespace, and newlines are not modified.
Unix timestamp in seconds. Must match the Shop-Timestamp header value.
Treat as a plain string — do not decode it as hex.
When filled, shows whether this signature matches what the server would compute, plus a separate timestamp freshness check.