Regex Tester
Test regular expressions, inspect matches, and preview results instantly in your browser. No upload, no account.
Test a regular expression to see matches here.
How to use this tool
What this tool does and how it can help.
A regex tester lets you write a JavaScript regular expression, apply it to text, and inspect where and how it matches.
Common use cases include validating input patterns, parsing text for extraction, building search patterns, and debugging complex development filters.
- Use patterns to validate user input such as IDs, names, phone numbers, or custom formats.
- Parse and extract sections from logs, reports, or pasted content.
- Build search patterns quickly and verify edge cases before wiring them into code.
- Support testing in development and debugging sessions where you need fast feedback.
JavaScript regex flags change matching behavior. g enables global matching, iignores case, m makes ^ and $ match line boundaries, sallows dot to match newlines, u enables full Unicode handling, and yenables sticky matching.
FAQ
- Is my text uploaded anywhere?
- No. Everything is processed locally in your browser.
- Can I test regex flags like g and i?
- Yes. You can provide standard JavaScript regex flags such as g, i, m, s, u, and y.
- What happens if my regex is invalid?
- The tool shows an error message instead of crashing.