regex101: build, test, and debug regex
Online regex tester and debugger with real-time match highlighting, detailed explanations, substitutions, unit tests, benchmarking, …
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 …
RegExr: Learn, Build, & Test RegEx
Regular expression tester with syntax highlighting, PHP / PCRE & JS Support, contextual help, cheat sheet, reference, and …
Regular expression - Wikipedia
The phrase regular expressions, or regexes, is often used to mean the specific, standard textual syntax for representing patterns for …
SimpleRegex - Online Regular Expression Tester & Generator
Test, visualize, and learn regular expressions with SimpleRegex. A fast, privacy-first regex tester with real-time highlighting, pattern …
Regular expression syntax cheat sheet - JavaScript | MDN
Aug 27, 2026 · This page provides an overall cheat sheet of all the capabilities of RegExp syntax by aggregating the content of the …
Regular Expression Language - Quick Reference - .NET
Jun 18, 2022 · A regular expression is a pattern that the regular expression engine attempts to match in input text. A pattern consists …
Regular expressions - JavaScript | MDN - MDN Web Docs
Mar 17, 2026 · A regular expression pattern is composed of simple characters, such as /abc/, or a combination of simple and special …
Regular expression HOWTO — Python 3.14.7 documentation
18 hours ago · Regular expressions (called REs, or regexes, or regex patterns) are essentially a tiny, highly specialized programming …
JavaScript Regular Expressions - W3Schools
Regular expression flags are parameters that can modify how a pattern is used, such as making it case-insensitive or global. These …