Regex Generator & Tester - Build and Test Regular Expressions Online
Build, test, and visualize regular expressions interactively. Highlights matches in real time, shows match details and groups, with common pattern presets.
Generators
Tool
Regex Pattern
Flags:
Test String
Common Patterns
How to Use
1Enter a regex pattern in the pattern field, or click a common pattern preset (email, URL, phone, etc.)
2Type or paste test text in the test string area to see matches highlighted in real time
3Toggle flags (global, case-insensitive, multiline) and copy your final pattern
Frequently Asked Questions
This tool uses JavaScript's built-in RegExp engine, which follows the ECMAScript standard. It supports most common regex features including lookaheads, character classes, quantifiers, and named groups.
The global (g) flag makes the regex find all matches in the string instead of stopping after the first match. Without it, only the first match is returned.