How to use Java Regex Tester
- Start by adding the pattern and test string you want to check into Java Regex Tester.
- Use the Pattern, Flags settings to control the result.
- Watch the output update instantly while you adjust the pattern and test string.
- Use Copy matches to keep or reuse the result.
About this tool
Java Regex Tester is a static, client-side tool with no backend. Java Regex Tester tests your regular expression against sample text in your browser, highlighting matches as you type.
Your pattern and test text stay on your device. No data is sent anywhere, so it stays fast and private by default.
Frequently asked questions
How do I use Java Regex Tester?
Use Java Regex Tester to check your input without installing anything using the Pattern, Flags controls; everything happens client-side.
Does Java Regex Tester cost anything?
No — Java Regex Tester is completely free, with no sign-up and no hidden limits.
Where is my data processed by Java Regex Tester?
Entirely in your browser — Java Regex Tester keeps your data on your own machine and sends nothing anywhere.
Which regex flavor does Java Regex Tester use?
Java Regex Tester runs your pattern with the browser's own JavaScript regex engine, live and on your device.
Can I use Java Regex Tester without a connection?
Yes — after the first load Java Regex Tester runs entirely offline.