🔎Regex Tester
Enter a regex pattern and flags (gimsuy) to see live matches. Supports capture groups and replacement preview. Useful for data extraction, writing input validation rules, log analysis, previewing VS Code or IDE search patterns, and learning regex.
How to use
- 1Enter your regex pattern.
- 2Enter test text.
- 3Choose flags (g, i, m, etc.).
- 4Matches and capture groups display automatically.
FAQ
Which engine is used?+
Your browser's JavaScript regex engine. ECMAScript standard, with full lookahead/lookbehind support.
Is it compatible with Python or Java regex?+
Core syntax is similar but some advanced features (named groups syntax, etc.) differ. Use language-specific testers for other languages.
Difference between flags (g, i, m, s, u, y)?+
g (global), i (case-insensitive), m (multiline), s (dot matches newline), u (unicode), y (sticky).
What are capture groups?+
Parts wrapped in parentheses ( ) can be extracted separately. In JavaScript, accessed via match[1], match[2], etc.
Are there email/phone regex examples?+
Email RFC is very complex. Practical patterns like 'name@domain' validate well but 100% coverage is hard.
Regex is hard — learning resources?+
Sites like regex101.com offer great visualization. This tool is for quick testing.