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Regex Tester

Test regular expressions with real-time highlighting and match details. Free and private.
Live Highlighting

See matches highlighted in real-time as you type your pattern.

All Flags

Toggle global, case-insensitive, multiline, dotAll, and Unicode flags.

Quick Presets

One-click patterns for email, URL, phone, IP, date, and more.

100% Client-Side

Uses your browser regex engine. No server, works offline.

Common Patterns
Email
URL
Phone
IPv4
Date
Hex Color
HTML Tag
Numbers

/

/g

Test String

Free Online Regex Tester

Regular expressions (regex) are patterns used to match character combinations in strings. They are essential for text processing, validation, search-and-replace operations, and data extraction. This tool lets you write, test, and debug regex patterns with instant visual feedback.

Regex Flags Explained

  • g (global): Find all matches instead of stopping after the first match.
  • i (case-insensitive): Match letters regardless of case. "abc" matches "ABC".
  • m (multiline): Makes ^ and $ match the start/end of each line, not just the string.
  • s (dotAll): Makes the dot (.) match newline characters (\n) as well.
  • u (unicode): Enables full Unicode matching, including surrogate pairs and Unicode property escapes.

Tips for Writing Regex

Start with simple patterns and build up. Use the preset patterns as starting points. Remember to escape special characters (. * + ? ^ $ { } [ ] | ( ) \) with a backslash when you want to match them literally. Use capture groups to extract specific parts of a match, and use non-capturing groups (?:...) when you only need grouping without capturing.

Frequently Asked Questions

This tool supports all standard JavaScript regex flags: g (global), i (case-insensitive), m (multiline), s (dotAll - dot matches newlines), and u (Unicode). Toggle any combination of flags using the flag buttons.

Yes, completely free with no limits. Test as many patterns as you want. No signup or account required.

Yes. Named and numbered capture groups are fully supported. When your pattern contains groups, the match details panel shows each group value alongside the full match.

We provide quick-start presets for Email, URL, Phone Number, IPv4 Address, Date (YYYY-MM-DD), Hex Color, HTML Tag, and Number patterns. Click any preset to load it instantly.

Yes. All regex testing happens in your browser using native JavaScript regex engine. No data is sent to any server. The tool works offline after the page loads.

Enable the m (multiline) flag to make ^ and $ match the start/end of each line. Enable the s (dotAll) flag to make the dot (.) match newline characters as well.

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