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

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 match or …

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.

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 …

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 …

RexExp Flags / Modifiers Flags can be added to a regexp pattern to modify its behavior:

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.

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 information from text by …

The one-page guide to regexp: usage, examples, links, snippets, and more.

Regular expressions is a powerful way of doing search and replace in strings. Unicode: flag "u" and class \p {...} Sets and ranges [...]