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 …

The phrase regular expressions, or regexes, is often used to mean the specific, standard textual syntax for representing patterns for matching text, as distinct from the mathematical notation described below.

Dec 8, 2025 · Character class: Matches any one of the enclosed characters. You can specify a range of characters by using a hyphen, but if the hyphen appears as the first or last character enclosed in the …

Apr 12, 2024 · Here's how to write regular expressions: Start by understanding the special characters used in regex, such as ".", "*", "+", "?", and more. Choose a programming language or tool that …

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.

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

Oct 29, 2025 · This quick reference is a summary of all the regex syntax that is listed in the full reference tables, without any explanation. You can use this table if you’ve seen some syntax in somebody …

Mar 1, 2025 · If you’ve ever needed to find specific text in a large document, validate user input, or extract key information from messy data, you’ve probably encountered regular expressions —often …

And while there is a lot of theory behind formal languages, the following lessons and examples will explore the more practical uses of regular expressions so that you can use them as quickly as possible.