Regex Tester
Test and debug regular expressions with live matching and highlighting
How to Use Regex Tester
- Enter your regex pattern in the pattern field
- Paste your test text in the input area
- Matches are highlighted automatically as you type
- Toggle flags (global, case-insensitive, multiline) as needed
About Regex Tester
Test and debug your regular expressions with live matching and visual highlighting. See matches instantly as you type, with support for JavaScript regex syntax. Perfect for building and validating patterns for form validation, text parsing, or data extraction.
Frequently Asked Questions
What regex flavor does this tool use?
This tool uses JavaScript's built-in RegExp engine. Most common regex features are supported, but some advanced features from other flavors may not work.
Why isn't my regex matching anything?
Check your flags (g for global, i for case-insensitive, m for multiline). Also verify your pattern syntax is correct.
How do I match across multiple lines?
Enable the multiline (m) flag. The dot (.) doesn't match newlines by default; use [\s\S] to match any character including newlines.
Can I use capture groups?
Yes, parentheses create capture groups. The tool highlights matches, but doesn't currently show individual group captures.