Regex
Regex Tester
Test and debug regular expressions against sample text with real-time matches.
Common: g (global), i (ignore case), m (multiline)
Run the tester to see matches for your pattern.
About Regex Tester
This Regex Tester provides a real-time environment to validate and debug your regular expression patterns. It highlights pattern matching results instantly, helping you visualize how your regex interacts with sample text and capture groups.
Write robust code by testing your expressions before deployment. Regex is powerful but brittle; ensuring you handle edge cases and regex flags correctly prevents runtime errors in production. This tool breaks down complex queries into understandable matches.
Enter your regex pattern (e.g., ^\d{5}$ for zips) and input a test string. The matching substrings are highlighted. You can inspect specific regex groups and modify flags (like Global or Case Insensitive) to refine your logic.
Under the Hood
This tool interfaces directly with the browser's native JavaScript `RegExp` engine. Highlight generation is done by iterating through `exec()` matches and building a React fragment tree that wraps matched indices in styled `span` tags. Group capturing uses the result array from the match object. Since it runs in the client browser, it perfectly mimics the regex behavior of the user's deployed JS environment.