Write regex patterns and see matches highlighted in real-time. Test against any text, right from your browser.
/https?:\/\/[^\s]+/g
See matches highlighted as you type your pattern. No submit button, no waiting — results update on every keystroke.
Capture groups, named groups, and backreferences are color-coded so you can see exactly what each part of your pattern captures.
Start with built-in patterns for emails, URLs, IPs, dates, and more. Modify them to fit your exact use case.
Move from JSON to JWT, regex, URLs, clipboard history, and color work without leaving the current page.
Yes. ArcPanel uses the browser's native RegExp engine, so every JavaScript regex feature is supported — including Unicode property escapes, dotAll mode, and named capture groups.
Yes. You can add multiple patterns and see them highlighted simultaneously with distinct colors, making it easy to compare or layer matches.
Yes. Positive and negative lookahead (?=...) (?!...) and lookbehind (?<=...) (?<!...) are fully supported, as they run on your browser's native regex engine.
Install the ArcPanel Chrome extension, open it with ⌘⇧K (or Ctrl+Shift+K on Windows/Linux), and search for Regex Tester. The tool opens instantly beside the page.
Page-aware side panel for instant browser actions.
Add to Chrome — Free