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Free Regex Tester Online – Test Regular Expressions with Live Highlighting
Test and debug regular expressions online for free. Real-time match highlighting, capture groups, and all JS flags (g, i, m, s). No signup required. Try now!
✅ 100% Free⚡ Instant Results🔒 No Signup📱 Mobile Friendly🔐 No Data Stored
Regex Tester
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Quick examples:
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Common Use Cases
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Form Validation
Build and test email, phone, URL, and password validation patterns before implementing in code.
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Log File Parsing
Create patterns to extract IPs, timestamps, and error codes from log files.
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Find & Replace
Test search patterns before using in code editor find-and-replace or text processing scripts.
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URL Pattern Matching
Build regex patterns for URL routing and path matching in Express.js and Next.js.
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Data Cleaning
Test patterns to remove unwanted characters and invalid data in text processing pipelines.
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Security Validation
Verify input sanitization patterns that filter SQL injection and XSS payloads.
Frequently Asked Questions
What regex syntax is supported?
JavaScript (ECMAScript) regex — compatible with JS, Java, Python (mostly), PHP, and Ruby.
What do the regex flags do?
g = all matches, i = case-insensitive, m = ^ and $ match line boundaries, s = dot matches newlines.
Can I test capture groups?
Yes — all capture groups and their matched values are displayed in the results panel.
What happens if my regex has an error?
A clear syntax error message appears immediately so you can identify and fix the issue.
Is the regex tester free?
Yes — completely free with no account or download required.