How to use the regex tester
Type a JavaScript regular expression (without wrapping slashes), toggle flags, and paste a test string. Choose Test to see the match count, highlighted matches when the text is a reasonable size, and capture groups. Invalid patterns show a clear error.
Frequently asked questions
How do I test a regular expression?
Enter the pattern, pick flags, and provide text. The results panel lists how many times it matched and the captured pieces of each match.
Which regex flags are supported?
g (global), i (case-insensitive), m (multiline), s (dotAll), and u (Unicode). These are the standard JavaScript flags for everyday testing.
What are capture groups?
Parentheses in a pattern create groups. Each match shows the full text plus numbered groups, and named groups when you used (?<name>…) syntax.
Is my test string uploaded?
No. Matching happens in your browser. Deskutil never receives the pattern or the text.