Regex Tester
Write and test regular expressions with real-time match highlighting. Supports JavaScript regex features including named groups, lookbehind, and the global, case-insensitive, multiline, and dotall flags.
How It Works
Write your regex pattern
Enter a regular expression pattern and select flags (g, i, m, s) using the checkboxes.
Enter test text
Type or paste the text you want to test against. Matches are highlighted in real time as you type.
Review matches
See all matches highlighted in the text with their capture groups and positions.
Frequently Asked Questions
Which regex features are supported?
All JavaScript regular expression features are supported, including named capture groups, lookbehind assertions, Unicode property escapes, and four flags: g (global), i (case-insensitive), m (multiline), and s (dotall).
Does matching happen in real time?
Yes. Matches update instantly as you type your pattern or modify the test text. There is no need to click a button.
Is my data sent to a server?
No. All pattern matching runs in your browser using JavaScript's native RegExp engine. Nothing is sent to any server.
Does it show capture groups?
Yes. A match details table shows each match along with its capture groups ($1, $2, etc.), match index, and value. Up to 100 matches are displayed.