Build and test regular expressions with real-time match highlighting, group extraction, and common presets.
A Regex Tester lets you write and test regular expressions interactively against sample text, with real-time match highlighting. Regular expressions (regex) are pattern-matching rules used for validation, extraction, search-and-replace, and text parsing across every programming language.
Matches are highlighted as you type — no need to run your code to see which parts of the text match. Multi-match mode highlights all occurrences simultaneously with distinct colors for each capture group.
The g flag finds all matches (not just first). i makes matching case-insensitive. m makes ^ and $ match line starts/ends. s makes . match newlines.
8 common patterns included: email, URL, IPv4 address, phone number, date, hex color, UUID, and URL slug. Use them as starting points or references for building your own patterns.
Parentheses create capture groups that extract sub-matches. The tool shows each group's matched value in a table below the main match — essential for extracting structured data from unstructured text.