Regex Cheat Sheet

The Regex Cheat Sheet is a free, interactive reference for regular expression syntax that every developer needs at their fingertips. Instead of memorizing cryptic metacharacters or digging through documentation, you can search, filter by category, and click to copy any syntax token in seconds.

Every entry includes the syntax notation, a plain-English description, an example pattern, and sample matches so you can immediately understand what each construct does. Categories cover the full spectrum of regex: character classes like \d, \w, and [a-z]; quantifiers including *, +, ?, and {n,m}; anchors such as ^, $, and \b; grouping constructs for capture, non-capture, and named groups; lookahead and lookbehind assertions; and all six JavaScript regex flags.

The built-in "Try It Live" area lets you enter any pattern and test string to see matches highlighted in real time, complete with flag toggles for global, case-insensitive, multiline, dotall, unicode, and sticky modes. This makes it easy to experiment with patterns before using them in your code.

A quick reference section of common patterns covers email validation, URL matching, IP addresses, dates, phone numbers, and hex color codes — patterns you reach for repeatedly.

All processing runs entirely in your browser. No data is sent to any server, and no login or signup is required. If you need to test regex patterns more thoroughly with capture group inspection and replace preview, try the Regex Tester. For building cron expressions that also use pattern-like syntax, check out the Cron Expression Builder. And for another searchable reference tool, the HTTP Status Codes reference follows a similar interactive format.

1. Type a keyword into the search bar at the top — for example, lookahead, digit, or quantifier.
2. Click a category badge (Character Classes, Quantifiers, Anchors, Groups, Assertions, Flags, Common Patterns) to filter the list.
3. Click any entry row to expand it and view the syntax, example pattern, and example matches.
4. Click the Copy Syntax button to copy the raw syntax token to your clipboard.
5. Scroll down to the Try It Live section to enter your own regex pattern and test string.
6. Toggle the flag buttons (g, i, m, s, u, y) to control matching behavior.
7. Review the highlighted Results area to see which parts of your test string match the pattern.