Regex tester and visualizer
Write a regular expression and see matches highlighted as you type. Capture groups are listed, replacements can be previewed, and an explanation breaks the pattern into readable parts. A timeout protects the page from runaway patterns.
Tooloat runs in your browser and needs JavaScript. It opens in a moment, and your files are processed on your device.
How it works
- Enter your pattern and flags.
- Paste the text to test.
- Review the matches, groups and the explanation.
Why use it
- Live highlighting of matches.
- Capture groups and named groups.
- Replacement preview.
- Timeout guard against catastrophic backtracking.
Questions and answers
Which regex flavor is used?
JavaScript, as implemented by your browser.
What if my pattern hangs?
Matching runs in a worker with a 1.5 second limit, so the page stays responsive and you get a warning.
Is my text uploaded?
No.
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