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

Oct 5, 2022 · The character class [A-z] will match every character between those characters, which in ASCII includes some other characters such as ' [', '\' and ']'. An alternative to specifying both cases …

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 …

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 …

For example, by defining a character style that makes text into small caps and then using the regex [A-Z]{4,} to apply that style, any word of four or more consecutive capital letters will be automatically …

Mar 17, 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 …

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

If you are a complete beginner, you should get a firm grasp of basic regex syntax just by reading the examples in the tables. I tried to introduce features in a logical order and to keep out oddities that I've …

A quick reference for regular expressions (regex), including symbols, ranges, grouping, assertions and some sa

Here is a quick tutorial for you to learn regular expressions, you can see the details about each individual topic also.