Regex Tester & Evaluator – Test Regular Expressions Online
Test, evaluate, and match regular expressions against test text inputs in real-time. All conversions and calculations happen locally inside your browser memory — no data is ever transmitted over network connections.
Regex Tester
⚡ How Regex Tester Works
Enter Pattern & Flags
Type regular expression pattern (e.g., ^[a-z0-9_-]+$) and flags (g, i, m).
Input Test Text
Provide target test string to evaluate matches dynamically.
Inspect Highlighted Matches
View capture groups, match indexes, and regex evaluation results.
💻 Code Example & Output
Evaluates pattern matching against test text with visual highlight indicators.
Regex: /[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}/g
Text: Contact support@htmlcompiler.in for help.Match 1: "support@htmlcompiler.in" (Index: 8-32)🎯 Key Use Cases for Regex Tester
Form Input Field Validation
Test custom regular expressions for email validation, strong passwords, and phone numbers.
Web Scraping & Text Extraction
Build regex capture patterns to parse data from HTML source files or log streams.
Search & Replace Refactoring
Validate complex regex patterns before running find-and-replace operations in VS Code.
Server Router Rule Testing
Verify URL rewrite patterns for Nginx, Apache, or Next.js middleware routing.
💡 Frequently Asked Questions
Q: Which Regex engine is used?
It uses standard JavaScript ECMAScript RegExp engine running natively in your browser.
Q: What do the flags g, i, and m mean?
g = Global match, i = Case-insensitive search, m = Multiline mode (anchors ^ and $ match line starts/ends).
Q: Is my input text sent anywhere?
No, all regular expression evaluations run locally inside your browser.
Q: How do I test capture groups?
Enclose sub-patterns in parentheses (...) to create numbered capture groups visible in match details.
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