Test and debug regular expressions in real time with this free online regex tester. See matches highlighted instantly as you type — no signup, no tracking. Runs 100% in your browser.
How to Use This Regex Tester
- Enter your regex pattern in the pattern field
- Set flags (g = global, i = case-insensitive, m = multiline)
- Paste your test string below
- Matches appear instantly as you type
- Use common patterns buttons for quick starts
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Regex Quick Reference
.— any character except newline\d— digit (0-9),\w— word char,\s— whitespace*— 0 or more,+— 1 or more,?— 0 or 1{n,m}— between n and m occurrences[abc]— character class,[^abc]— negated class^— start of string,$— end of string(group)— capture group,(?:group)— non-capturinga|b— alternation (a or b)
Common Regex Flags
g— Global: find all matches, not just the firsti— Case-insensitive matchingm— Multiline:^and$match line boundariess— Dotall:.matches newlines too
Privacy
This regex tester runs entirely in your browser. No data is sent to any server. Safe for testing patterns against sensitive text.
Recommended Reading
Master regular expressions with these essential resources:
- Mastering Regular Expressions — essential reading for learning regex
- Regular Expressions Cookbook — essential reading for regex patterns
- Introducing Regular Expressions — essential reading for getting started with regex
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