RegEx Tester & Explainer
Create and test Regular Expressions in real-time. Highlights match patterns, captures match indexes, and exposes groupings.
RegEx Configuration
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Real-time Match Visualization
Contact support@company.com or hello_world123@sub.domain.co for more info.
Matches Summary (0)
No active matches found.
Frequently Asked Questions
Does this regular expression tester send my input to a server?
No. All pattern parsing, regular expression compilation, and match highlighting execute entirely in your local browser using JavaScript’s native RegExp engine.
What regex flags are supported?
Standard ECMAScript flags are supported, including g (global search), i (case-insensitive), m (multiline anchor matching), s (dotAll mode allowing dots to match newlines), and u (full Unicode support).
How does the tool prevent catastrophic backtracking?
The tester executes safety counters and limits match iteration loops so that runaway nested quantifiers do not freeze the browser interface.
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