How to use Java Regular Expression Tester
- Enter or paste your text into the input field to begin.
- Use the Pattern, Flags settings to control the result.
- Java Regular Expression Tester updates the output automatically as you type.
- When it looks right, Copy matches to save it.
About this tool
Java Regular Expression Tester is a static, client-side tool with no backend. Java Regular Expression Tester tests your regular expression against sample text in your browser, highlighting matches as you type.
Flags and group captures are surfaced so you can refine the pattern quickly. Nothing you enter is uploaded, and it keeps working offline once the page has loaded.
Frequently asked questions
What does Java Regular Expression Tester do?
Java Regular Expression Tester lets you check your input right in the browser using the Pattern, Flags controls, with the result shown instantly and nothing uploaded.
Does Java Regular Expression Tester cost anything?
No — Java Regular Expression Tester is completely free, with no sign-up and no hidden limits.
Is my input private in Java Regular Expression Tester?
Yes — your input never leaves your device; Java Regular Expression Tester does all the work in your browser.
Which regex flavor does Java Regular Expression Tester use?
Java Regular Expression Tester runs your pattern with the browser's own JavaScript regex engine, live and on your device.
Can I use Java Regular Expression Tester without a connection?
Yes — after the first load Java Regular Expression Tester runs entirely offline.