How to Use Regex Tester
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1. Enter Your Regex Pattern
Type your regular expression pattern into the pattern field, including any flags (g, i, m, s).
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2. Paste Your Test String
Enter the text you want to test against in the test string area below.
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3. View Matches in Real Time
All matches are highlighted as you type, with match count and capture group details shown.
The Technical Details
This interactive web utility provides fast, reliable, and completely private data transformations. In modern workflows, quick formatting, conversions, or estimations are essential. By running all logic entirely in your browser with client-side JavaScript, this tool guarantees that your data never leaves your machine. This approach delivers maximum performance and absolute data privacy, as no information is ever sent to a server.
Frequently Asked Questions
Which regex flags are supported?
The tool supports all JavaScript regex flags: g (global), i (case-insensitive), m (multiline), s (dotAll), and u (unicode).
Are lookaheads and lookbehinds supported?
Yes. Positive and negative lookaheads and lookbehinds are supported in all modern browsers.
Is any data sent to a server?
No. All regex matching runs in your browser using the native JavaScript RegExp engine.
Where can I find common regex patterns?
Check the Regex Patterns cheatsheet on this site for ready-to-use patterns for emails, URLs, dates, and more.