Regex Tester
Free online regex tester and debugger. Test JavaScript regular expressions with real-time matching and syntax highlighting. Perfect for building and debugging regex patterns. No signup, local browser processing.
How to Use Regex Tester
- 1Enter your regular expression pattern in the pattern field
- 2Toggle regex flags (g, i, m, s, u) as needed
- 3Enter test text in the input area
- 4View highlighted matches in real-time
- 5Inspect capture groups for each match
Frequently Asked Questions
Which regex flavor does this tester use?
JavaScript / ECMAScript regex flavor is used. This matches exactly what runs in web browsers and Node.js, making it ideal for web developers building applications that will use regex in JavaScript environments.
Can I test regex patterns with multiple sample texts?
Yes, enter as many lines of test text as you need. The tool highlights all matches in real-time and shows capture groups for each match individually, making it easy to test your pattern against various inputs at once.
Does it support regex flags like global and case-insensitive?
Yes, you can toggle standard regex flags including g (global), i (case-insensitive), m (multiline), s (dotAll), and u (unicode). Each flag is explained so you understand exactly how it affects your pattern matching.
Is Regex Tester free, and do I need to sign up or upload my files?
Regex Tester is 100% free to use with no signup, no registration, and no usage limits. All processing happens locally in your browser - your files and data never leave your device, so no upload is required and your privacy is fully protected.