Free Regex Tester
Use our free regex tester to test and debug regular expressions online. Real-time matching, highlighting, and capture group analysis.
- Real-time match highlighting
- Capture group display
- Match detail information
- Pattern explanation
- Multiple regex flavors
- Common patterns library
Frequently Asked Questions
What regex syntax is supported?
JavaScript regex by default, with options for Python, PCRE, and other flavors. Syntax differences are highlighted when switching flavors.
How do I see capture groups?
Capture groups are highlighted in different colors. Hover over matches to see numbered groups and their values. Named groups are also supported.
Why isn't my pattern matching?
Common issues: forgetting to escape special characters, incorrect anchors, or wrong character classes. Use the pattern explanation to understand what your regex is actually doing.