Free Regex Tester Online
Test regular expressions with real-time match highlighting, flag support, and capture group display.
Key Features
Everything you need to test and debug regular expressions
Matches are highlighted in the test text instantly as you type, making it easy to see what your pattern captures.
Each match is listed with its position and any capture groups so you can inspect results precisely.
All processing runs locally in your browser. Your patterns and text never leave your device.
How to Convert Files
Upload your files, select output format, and download converted files instantly. Our converter supports batch conversion and maintains high quality.
Frequently Asked Questions
Is this tool completely free?
Yes. The tool is 100% free to use with no registration, no subscription and no usage limits.
You can use it as many times as you need for personal or commercial projects without any cost.
We believe developer and productivity tools should be accessible to everyone without paywalls.
What do the regex flags do?
The g flag finds all matches in the text instead of stopping after the first. The i flag makes matching case-insensitive.
The m flag makes ^ and $ match the start and end of each line rather than the whole string.
The s flag (dotAll) makes the dot character match newlines as well as other characters.
How do I use capture groups?
Wrap part of your pattern in parentheses to create a capture group, for example (\d+) to capture a sequence of digits.
The match list will show each group value alongside the full match so you can see exactly what was captured.
Named groups using the (?
What regex engine does this tool use?
The tool uses the JavaScript RegExp engine built into your browser, so results match exactly what you would get in a JavaScript application.
This makes it ideal for testing patterns intended for use in front-end JavaScript or Node.js projects.
Patterns for other languages such as Python or PHP may differ slightly in syntax and behavior.