About Regex Tester

The Regex Tester is a powerful and free online tool that helps you test, debug, and validate regular expressions in real time. It allows you to apply regex patterns to sample text and instantly view matches, highlights, and results, making it easier to understand and fix even complex expressions.

This tool runs completely in your browser, which means your data is never uploaded or stored on any server. It is fast, secure, and ideal for developers, testers, students, and anyone working with pattern matching, form validation, or text processing.

Key Features

• ✔ Test regular expressions instantly
• ✔ Support for common regex flags (g, i, m, s)
• ✔ Highlight all matched text clearly
• ✔ Display total match count and index positions
• ✔ Clear and helpful error messages for invalid regex
• ✔ Clean, fast, and developer-friendly interface
• ✔ 100% browser-based and privacy-safe

Common Use Cases

• ✔ Validating user input and form patterns
• ✔ Debugging and testing regular expressions
• ✔ Learning and practicing regex concepts
• ✔ Searching, extracting, and filtering text data

How to Use

1. Enter your regular expression in the regex input field.
2. Select the required flags (g, i, m, s) if needed.
3. Paste your test string into the text area.
4. Click Run Regex to view matches and highlighted results.

For a complete development and productivity workflow, you may also find these tools helpful: HTML / CSS / JS Minifier, JSON Formatter & Validator, Base64 Encoder / Decoder, CSV to JSON Converter.