Regex Tester
Test and debug regular expressions in real-time with match highlighting.
Regular expressions (regex) are powerful pattern-matching tools used extensively in programming, data validation, and text processing. Our regex tester provides a real-time environment to write, test, and debug regular expressions with instant visual feedback.
As you type your pattern, the tool instantly highlights all matches in your test string, showing you exactly what your regex captures. Capture groups are displayed separately, making it easy to verify that your pattern extracts the correct data. The flag controls (g, i, m, s) let you modify behavior without editing the pattern itself.
We also include a library of common regex patterns for frequent tasks like email validation, URL matching, phone numbers, IP addresses, and more. These patterns serve as starting points that you can customize for your specific needs.
Debugging regex can be frustrating without visual feedback. Our tester shows matches in real-time, displays capture groups clearly, and includes common patterns as templates. Everything runs in your browser.
- Enter your regular expression pattern
- Type or paste your test string
- View matches highlighted in real-time
- Start with simple patterns and gradually add complexity — it is easier to debug incrementally.
- Use the global flag (g) to find all matches, not just the first one.
- The case-insensitive flag (i) is useful when you don't care about letter casing.
- Use non-capturing groups (?:...) when you need grouping but don't need to capture the match.
- Escape special regex characters (. * + ? ^ $ {} [] | () \) with a backslash when matching them literally.
- Test edge cases: empty strings, very long inputs, and special characters.