Free Regex Tester & Pattern Generator

Test regular expressions with live highlighting, plain-English suggestions, and 50+ pre-built patterns for email, URL, and phone. Free regex tester for developers.

How to Use Free Regex Tester & Pattern Generator

1. Enter a regular expression in the pattern field and select flags (g, i, m, s) as needed
2. Type or paste your test string to see live highlighted matches and group captures
3. Browse the 50+ pattern library for emails, URLs, phone numbers, and dates
4. Click any pattern to load it into the tester, then customize it for your specific case

Frequently Asked Questions

How do I match an email address with regex?

A basic email regex: /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/ — load this from our email pattern in the library and test it with your input directly in the tester.

What regex flags should I use?

Common flags: g (global — find all matches), i (case insensitive), m (multiline — ^ and $ match line boundaries), s (dotAll — dot matches newlines). Combine as needed: /pattern/gi

What is a regex capture group?

Parentheses () create capture groups that extract specific parts of a match. Example: /(\d{4})-(\d{2})-(\d{2})/ on '2026-04-15' captures year, month, and day separately. Our tester shows all captured groups.

What is the difference between .* and .+?

.* matches zero or more characters (including none). .+ matches one or more characters (at least one required). Use .* when the pattern may be absent, .+ when at least one character must be present.

Is this regex tester free to use?

Yes, completely free with no signup. Test unlimited patterns, access the full pattern library, and get plain English explanations for any regular expression.

Can I test regex across multiple languages?

Our tester uses the JavaScript regex engine (PCRE-like). Most syntax is compatible with Python, Java, and PHP. Some lookbehind and atomic group features differ between engines — we label JavaScript-specific syntax in the pattern library.