regex101: build, test, and debug regex
Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/.NET, Rust.
RegExr: Learn, Build, & Test RegEx
RegExr is an online tool to learn, build, & test Regular Expressions (RegEx / RegExp).
Regex Tutorial - How to write Regular Expressions
Dec 22, 2025 · A regular expression (regex) is a sequence of characters that defines a search pattern. It is mainly used for pattern matching in strings, such as finding, replacing, or validating text. Regex is …
Regex Cheat Sheet - rexegg.com
Regular Expressions Syntax Reference. Includes tables showing syntax, examples and matches.
Regular expression - Wikipedia
A regular expression (shortened as regex or regexp), [1] sometimes referred to as a rational expression, [2][3] is a sequence of characters that specifies a match pattern in text. Usually such patterns are …
Regular expression syntax cheat sheet - JavaScript | MDN
Mar 17, 2026 · Regular expression syntax cheat sheet This page provides an overall cheat sheet of all the capabilities of RegExp syntax by aggregating the content of the articles in the RegExp guide. If …
SimpleRegex - Free Online Regex Tester & Pattern Generator
Test and generate regular expressions in real-time. Free online regex tool for developers with syntax highlighting, pre-built examples, and instant match results.
Python RegEx - W3Schools
A RegEx, or Regular Expression, is a sequence of characters that forms a search pattern. RegEx can be used to check if a string contains the specified search pattern.
Regular expression HOWTO — Python 3.14.6 documentation
2 days ago · Regular expression HOWTO ¶ Author: A.M. Kuchling <amk @ amk. ca> Abstract This document is an introductory tutorial to using regular expressions in Python with the re module. It …
regex101: build, test, and debug regex
Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java. Features a regex quiz & library.