10 Regex Patterns Every Developer Should Know (With Live Examples)

10 Regex Patterns Every Developer Should Know Regular expressions are one of those things you use daily but never feel fully comfortable with. Here are 10 patterns that solve real problems, with explanations so you actually understand them. Test these patterns live: aiforeverthing.com/regex-tester.html — paste the patterns and test strings directly. 1. Email Address \b[\w.+-]+@[\w-]+\.[\w.]{2,}\b Test string: Contact alice@example.com or support@dev.io for help. Breakdown: [\w.+-]+ — local part (letters, digits, dots, plus, hyphen) @ — literal @ [\w-]+ — domain name \. — literal dot [\w.]{2,} — TLD (at least 2 chars, allows dots for co.uk ) Note: The perfect email regex is famously complex. This catches 99% of real emails without complexity. 2. URL (HTTP/HTTPS) https?://[\w-]+(\.[\w-]+)+([/\w.,@?^=%&:~+#-]*[\w@?^=%&/~+#-])? Test string: Visit https://example.com/path?q=1&sort=asc or http://dev.io The s? makes https optional, and the capture group at the end handles query strings and fr