You are responsible for key management and output validation.
Regex Tester
Test regular expressions live in your browser. See every match with groups and indices, with support for common flags. Zero-knowledge, client-side only.
Matches
2 matches| # | Index | Match | Groups | |
|---|---|---|---|---|
| 1 | 0 | Zero-knowledge | 1=Zero | |
| 2 | 103 | zero-knowledge | 1=zero |
Frequently Asked Questions
Which regex flavors are supported?
The tester uses JavaScript's native RegExp engine, the same flavor used by Node.js and modern browsers. Quantifiers, groups, lookarounds, and Unicode properties behave as they do in JavaScript.
Are my pattern and test text uploaded?
No. Matching runs entirely in your browser with the native RegExp engine. Nothing is sent to a server, so you can safely test patterns against sensitive logs or configuration.
How do I avoid regex performance problems?
Keep patterns linear where possible and avoid nested quantifiers like (a+)+ which can cause catastrophic backtracking on certain inputs. Test against realistic input sizes before deploying.