About This Tool
The Regex Tester lets you build and test regular expressions in real-time. See matches highlighted in your test string, view capture groups, and experiment with different flags — all with instant feedback as you type.
How to Use
- Enter your regular expression pattern
- Set flags (g for global, i for case-insensitive, m for multiline)
- Type or paste your test string
- Matches are highlighted in real-time
- View match details including capture groups below
FAQ
What regex flavor does this use?
This tool uses JavaScript’s built-in RegExp engine, which supports ECMAScript regex syntax including lookahead, lookbehind, and named capture groups.
Does this support multiline patterns?
Yes. Add the ‘m’ flag to enable multiline mode where ^ and $ match the start and end of each line.
