Regex Generator

The Regex Generator is a free regex generator and regex library that gives you proven regular expressions for the patterns developers need constantly — email addresses, URLs, IPv4 addresses, ISO dates, times, hex colors, UUIDs, slugs, usernames, numbers, strong passwords and HTML tags — without hand-writing or half-remembering them from an old project.

Looking up a regex for email validation, or any of the other common patterns, usually means digging through old code, a Stack Overflow answer of uncertain quality, or writing one from scratch and hoping it handles the edge cases. This tool curates the well-tested version of each pattern, shows a plain description of what it matches, and gives a concrete example string so you can confirm it's the pattern you actually need before copying it into your code. The IPv4, UUID and hex color patterns in particular save real debugging time, since a subtly wrong hand-written version of any of them — one that accepts 999.999.999.999 as a valid IP address, for instance — can pass casual testing and only fail once it meets real-world data.

Every pattern supports toggling anchoring (^…$) and the common flags (g, i, m) independently, because the same underlying pattern is used differently depending on context: anchored and case-sensitive for validating a whole form field, unanchored and global for finding every match inside a larger block of text. The ready-to-copy regex literal — pattern plus flags — updates instantly as you change either setting.

Using a curated pattern is faster and safer than writing your own from memory: these patterns are chosen specifically to avoid classic pitfalls like unescaped dots that match any character, or nested quantifiers that cause catastrophic backtracking and hang your application on certain input.