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 on a …
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 …
regexp cheatsheet
The one-page guide to regexp: usage, examples, links, snippets, and more.
Regular expressions - The Modern JavaScript Tutorial
Regular expressions is a powerful way of doing search and replace in strings. Unicode: flag "u" and class \p {...} Sets and ranges [...]