Regex Tester
Test your regular expressions with real-time match highlighting. See all matches, capture groups, and match positions. Everything runs in your browser — nothing is sent to a server.
/
What Is a Regular Expression?
A regular expression (regex) is a pattern that describes a set of strings. Programmers and data analysts use regex for searching, matching, and transforming text. Common use cases include validating user input (emails, phone numbers, dates), extracting structured data from logs, and performing search-and-replace operations across files.
How to Use This Regex Tester
Type your regex pattern in the input field and enter the text you want to test in the textarea below. Matches are highlighted in real time. Use the flags field to control matching behavior: g (global — find all matches), i (case-insensitive), m (multiline), and s (dotAll — dot matches newlines). Click any pattern in the Common Patterns sidebar to insert it instantly.