Regex Tester - Free Online Tool
Enter a regex pattern and test string to see all matches, capture groups, and a replace preview. Invalid patterns show a clear error.
Test regular expression
How to Use This Tool
- Enter your regular expression in the pattern box.
- Optionally add flags: g (global), i (ignore case), m (multiline).
- Paste or type the test string.
- Click Test to see matches and replace preview.
Benefits of Using This Tool
- Debug regex without leaving the browser.
- No signup; runs in your browser.
- See match index and groups at a glance.
When to Use Regex Tester
- Validate email or URL patterns before using in code.
- Test capture groups for parsing or replace logic.
- Quick sanity check for regex in config or scripts.
FAQs
Is my text sent to a server?
No. Testing runs entirely in your browser. Your pattern and text never leave your device.
Which regex flavor is used?
JavaScript RegExp (ECMAScript). Flags g, i, m are supported.
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