Regex Cheatsheet for Developers: Common Patterns with Examples

Regular expressions are one of those skills that pays dividends for years. Once you internalize the syntax, you can validate form inputs, parse log files, transform data, and search code — all with a few characters. This cheatsheet covers the essential regex syntax, the most useful patterns, and practical examples you can use directly. Test all patterns in your browser with the Regex Tester — paste a pattern, test it against real input, and see matches highlighted live. Core Syntax Reference Character Matching Pattern Matches . Any character except newline \d Digit (0-9) \D Non-digit \w Word character ([a-zA-Z0-9_]) \W Non-word character \s Whitespace (space, tab, newline) \S Non-whitespace \b Word boundary \B Non-word boundary ^ Start of string (or line with m flag) $ End of string (or line with m flag) \n Newline \t Tab Character Classes [abc] # Match a, b, or c [^abc] # Match anything except a, b, c [a-z] # Lowercase letters [A-Z] # Uppercase letters [0-9] # Digits (same as \d) [a-z