One of the most common and frustrating tasks for any web developer is writing a regular expression to validate a user's email address on a signup form. A regex that is too strict will reject obscure but valid business emails, frustrating customers. A regex that is too loose will allow spam and malformed inputs to flood your database. Our Regex Tester is the perfect sandbox for building and verifying an email validation pattern. You can paste in a large list of test cases—including standard emails, emails with plus-addressing (`user+tag@gmail.com`), new top-level domains (`.io`, `.museum`), and entirely invalid inputs.
By checking your regex in real-time, you can fine-tune the strictness. We recommend using the HTML5 specification regex, which provides an excellent balance of validation without incorrectly blocking valid users.