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Regex tester
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About this tool
Test JavaScript regular expressions with match positions, capture groups and replacement preview.
Common uses
- Test JavaScript regular expressions with match positions, capture groups and replacement preview.
- Enter a pattern without / delimiters and test text; select global, case-insensitive, multiline or dotAll options.
How to use it
- 1.Enter a pattern without / delimiters and test text; select global, case-insensitive, multiline or dotAll options.
- 2.Inspect highlighted matches and groups, and enter a nonempty replacement template to preview replacement.
Limits and notes
- Unicode mode is always on. Worker execution stops at 900 ms; limits include 200,000 input units, 2,000 pattern units, 5,000 matches and 500,000 output units. Match-only results can be truncated; replacement exceeding limits fails.
Frequently asked questions
What does this tool do?
Test JavaScript regular expressions with match positions, capture groups and replacement preview.
What should I check before using the result?
Unicode mode is always on. Worker execution stops at 900 ms; limits include 200,000 input units, 2,000 pattern units, 5,000 matches and 500,000 output units. Match-only results can be truncated; replacement exceeding limits fails.