Regex Tester
Test regular expressions against sample text with this free regex tester. Enter the raw pattern (no /slashes/), pick flags, and paste sample text to see highlighted matches, offsets, and capture groups - all in your browser.
Ideal for debugging email/URL patterns without shipping sensitive log lines to a third-party API. Invalid patterns surface the native SyntaxError under the Pattern field.
Sample text
Paste or type your content here…
Results
Enter a pattern and some text above to see matches highlighted.
Frequently Asked Questions
Where do I enter the pattern?
The Pattern field above the sample text. Flags g, i, m, s, u, and y are checkboxes next to it. Do not wrap the pattern in /slashes/.
Does it run on a server?
No - matching uses the browser RegExp engine in a Web Worker with a timeout against catastrophic backtracking.