How regex tester works
A regular expression (regex) is a pattern that matches text. Regex is used for validation, search-and-replace, data extraction, and parsing. This tester lets you write a pattern, apply it to test text, and instantly see all matches with their positions and capture groups.
Enter your pattern and optional flags (g for global, i for case-insensitive, m for multiline). The tester applies the regex to your test string and shows every match, its position in the text, and any capture groups. If the pattern is invalid, it shows the error message.
Regex can be complex, but the tester makes it interactive. Common patterns: d+ matches numbers, [a-z]+ matches lowercase letters, ^ and $ match start and end. Use capture groups with parentheses to extract parts of matches.