Regex Tester & Validator

Extracts the value of a "signature" key from JSON data using a positive lookbehind that matches the position immediately after `"signature":"`, then captures one or more characters up to (but not including) the closing double quote. Commonly used to pull signature strings, such as HMAC signatures or token values, out of API responses or embedded JSON without surrounding quotes. Note it only works for string values and will not match numeric or null values.