Regular expression tester with syntax highlighting, explanation, cheat sheet for PHP/PCRE, Python, GO, JavaScript, Java, C#/.NET, Rust.

RegExr is an online tool to learn, build, & test Regular Expressions (RegEx / RegExp).

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 …

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 …

Regular Expressions Syntax Reference. Includes tables showing syntax, examples and matches.

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.

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 …

Jun 18, 2022 · In this quick reference, learn to use regular expression patterns to match input text. A pattern has one or more character literals, operators, or constructs.

Test and generate regular expressions in real-time. Free online regex tool for developers with syntax highlighting, pre-built examples, and instant match results.

1 day 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 …