Free online Regular Expression Tester (Regex)
Our Regular Expression Tester (Regex) tool is completely free and works directly in your browser. Test your regex in real time with match highlighting and captured groups list. No signup required, no data sent to any server.
How to use this tool?
Simply fill in the fields above and the result appears instantly. Our regular expression tester (regex) supports regex, regular expression, pattern, flags. The tool is optimized for both mobile and desktop.
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What is a regular expression?
A regular expression (regex) is a pattern-matching language used to search, validate and extract text. It is supported in virtually every programming language including JavaScript, Python, PHP and Java.
How to test a regex online
Enter your pattern in the regex field, set flags (g for global, i for case-insensitive, m for multiline), type your test string and click Test. Matching parts are highlighted instantly and the full list of matches appears below.
Common regex patterns
- Email:
^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$
- URL:
https?:\/\/[^\s]+
- Phone (US):
\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}
Frequently Asked Questions
How do I test a regular expression online?
Enter your regex pattern in the first field, set the flags (g, i, m), type your test string and click Test. Matches are highlighted instantly in the output.
What regex flags are available?
Common flags: g (global, find all matches), i (case-insensitive), m (multiline, ^ and $ match each line). You can combine them, e.g., gi for global case-insensitive.
Can I generate regex patterns with this tool?
This tool is designed for testing. Type a pattern, see matches in real time, and iterate until your regex works correctly.
Is this regex tester free?
Yes, completely free with no sign-up. Everything runs in your browser using the native JavaScript regex engine.