Test text with regex
Run a JavaScript regular expression against supplied text.
Input & settings
How to use this tool
Enter the pattern without slash delimiters. Results include matched text, UTF-16 indices, captures and named groups.
Limits and behavior
Source limited to 64 KB, pattern 256 characters and 10,000 matches. Runs in a cancellable worker; pathological expressions may require Cancel. Browser regular expression support applies. Maximum total input 1 MB, output 3 MB, JSON nesting 64 levels. Processing stays in your browser worker. Input is limited to 1 MB and output to 3 MB. No input content is saved by CraftAI.
Check a regular expression against sample text
Enter your regex pattern and sample text to explore matching behavior using JavaScript regular-expression rules.
Does a regex test guarantee protection against slow patterns?
No. Complex or poorly chosen expressions can be expensive; avoid untrusted or pathological regex in production.
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