Regex Tester
Test and debug regular expressions with live highlighting.
About Regex Tester
What is Regex Tester?
The Regex Tester is an interactive tool for testing and debugging Regular Expressions (regex). You can write a regex pattern, set flags (global, case-insensitive, multiline), and test it against any input string. All matches are highlighted in real time, making it easy to see exactly what your pattern matches.
How to Use
- 1Enter your regex pattern in the Pattern field (without slashes).
- 2Select flags (g = global, i = ignore case, m = multiline).
- 3Type your test string in the Test String area.
- 4Matching text is highlighted instantly in green.
Frequently Asked Questions
Is the Regex Tester free to use?
Yes, the Regex Tester on RapidTools is 100% free. Like all our online utilities, there are no hidden fees, subscriptions, or sign-up requirements.
Does Regex Tester store my data?
No. The Regex Tester runs entirely in your web browser using JavaScript. No data from the tool is ever sent to our servers or stored permanently.
Do I need to install any software for Regex Tester?
No installation is required. This is a browser-based version of Regex Tester that works on any device with a modern web browser, including Windows, macOS, Linux, Android, and iOS.
100% Private — Your Data Never Leaves Your Browser
Uses the JavaScript RegExp constructor under the hood. Matching is performed on every keystroke using a debounced approach to ensure smooth performance.