Regex tester
Test regular expressions free in your browser with live match highlighting, capture groups and replace preview. 100% private, no upload, no sign-up.
100% private — files never leave your device//
0 matches
Replace with (use $1, $2 for groups)
How to use
- Enter a pattern. Type your regular expression between the slashes and set any flags you need.
- Add test text. Paste the text to match against; matches highlight live as you edit.
- Check groups. See the capture groups of the first match, including named groups.
- Preview a replace. Type a replacement using $1, $2 to see the substituted result instantly.
Features
- Live match highlighting. Every match is highlighted in your test text as you refine the pattern.
- Flag toggles. Switch global, ignore-case, multiline, dotall and unicode flags with checkboxes.
- Capture groups. Numbered and named capture groups of the first match are listed for you.
- Replace preview. See the result of a replacement using $1, $2 references in real time.
- Nothing leaves your device. Patterns and text are evaluated locally and never uploaded.
When to use it
- Craft a pattern to validate emails, phone numbers or slugs.
- Debug why a regex isn't matching the text you expect.
- Extract capture groups from log lines or structured text.
- Preview a find-and-replace before running it in your editor.
- Learn how flags like multiline and dotall change matching.
Is it private?
Patterns and text are evaluated locally in your browser and never uploaded.
Frequently asked questions
Is this regex tester free?
Yes, it's completely free with no sign-up and no limits.
Which regex flavour does it use?
JavaScript regular expressions, using your browser's built-in RegExp engine.
Is my pattern or text uploaded?
No. Everything is evaluated locally in your browser and never uploaded.
Does it show capture groups?
Yes. It lists numbered and named capture groups for the first match.
Can I preview a replacement?
Yes. Enter a replacement with $1, $2 references and see the result live.
Do I need to install anything?
No. It runs entirely in your web browser with nothing to install.
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