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
Menu RegExr is an online tool to learn, build, & test Regular Expressions (RegEx / RegExp). Supports JavaScript & PHP/PCRE RegEx. Results update in real-time as you type. Roll over a …
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.
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 …
Regular expression syntax cheat sheet - JavaScript | MDN
Jan 8, 2026 · 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 you need more information …
JavaScript RegExp Patterns - W3Schools
RexExp Flags / Modifiers Flags can be added to a regexp pattern to modify its behavior:
Regular-Expressions.info - Regex Tutorial, Examples and Reference ...
Jan 9, 2026 · A regular expression (regex or regexp for short) is a special text string for describing a search pattern. You can think of regular expressions as wildcards on steroids.
Regex Tutorial - A Cheatsheet with Examples - Regextutorial.org
Regular expressions or commonly called as Regex or Regexp is technically a string (a combination of alphabets, numbers and special characters) of text which helps in extracting …
RegexPlanet
Regular expressions are an incredibly powerful tool, but can be rather tricky to get exactly right. This is a website that I wrote so I could quickly and easily test regular expressions during …
regexp cheatsheet
The one-page guide to regexp: usage, examples, links, snippets, and more.