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About Regex Tester
Regex Tester is a powerful online tool for testing and debugging regular expressions in real-time. It supports standard JavaScript RegExp syntax, providing immediate feedback with highlighted matches and substitution previews. Whether you are a beginner learning regex or an expert debugging complex patterns, this tool helps you validate your expressions quickly.
How to Use
- Enter your regular expression pattern in the top input field.
- Select the desired flags (e.g., 'g' for global search, 'i' for case-insensitive).
- Type or paste your test text in the 'Test String' area.
- View the highlighted matches instantly in the 'Match Result' box.
- Optionally, use the 'Substitution' section to test replacement logic.
FAQs
Which regex engine is used?
This tool uses the native JavaScript RegExp engine running in your browser.
What does the 'g' flag do?
The 'g' (global) flag indicates that the regex should be tested against all possible matches in a string, not just the first one.