Regex Tester
Test regular expressions against text. See all matches instantly. Supports JavaScript regex.
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What is this tool?
Regex tester helps you create, test, and debug regular expressions in real-time. Regular expressions are patterns used to match character combinations in strings, essential for text search, validation, extraction, and replacement. This tool shows matches, captured groups, and supports common regex flavors including JavaScript and Python.
How to use
- 1
Enter regex pattern
Type your regular expression pattern.
- 2
Set flags
Choose flags like global (g), case-insensitive (i), multiline (m).
- 3
Enter test string
Paste the text to test against.
- 4
View matches
See all matches with captured groups highlighted.
Frequently Asked Questions
What does ^ and $ mean in regex?
The caret (^) matches the start of a string or line in multiline mode. The dollar sign ($) matches the end. Together they anchor a pattern to match the entire string. Without anchors, the pattern can match anywhere in the text.
What are regex groups?
Groups created with parentheses () capture matched text for later use. (\d{3})-(\d{4}) on "555-1234" captures group 1 = "555" and group 2 = "1234". Named groups (?<name>...) allow referencing by name. Non-capturing groups (?:...) match without saving.
Can I use this in production?
This tool is designed for development and testing. For production use established libraries with security audits.