One of the most common uses of regex in email marketing is to validate email addresses. A basic regex pattern for this might look like: /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/ This pattern checks for a string that starts with alphanumeric characters, followed by an '@' symbol, a domain name, and a top-level domain.