Regex Tester
Test and debug JavaScript regular expressions online. Our Regex Tester highlights matches in real-time against sample text to help verify patterns quickly.
Matches (9)
hehequickquickbrownbrownfoxfoxjumpsjumpsoveroverthethelazylazydogdogAbout the Regular Expression Tester
The Regex Tester by Coders Kit is an interactive tool to learn, build, and test Regular Expressions (RegEx) in real-time. RegEx is a powerful sequence of characters that specifies a search pattern, used for string searching (find) and manipulation (replace). Our tool highlights matches instantly as you type, helping you debut complex patterns.
Regex Features
Real-time Highlighting
Paste your text and type your pattern. We visually highlight every match in the text, so you can see exactly what your regex is capturing (and what it is missing).
JavaScript Flavor
We use the standard JavaScript RegExp engine. This ensures that the patterns you test here will work perfectly in your Node.js apps or frontend browser code.
Flags Support
Toggle common flags like g (global search), i (case insensitive), and m (multiline) to refine how your pattern matches against the text.
Common Regex Patterns
- Email:
^[\w-\.]+@([\w-]+\.)+[\w-]{2, 4}$- Validates standard email formats. - Date (YYYY-MM-DD):
^\d{4}-\d{2}-\d{2}$- Matches standard ISO date format. - Alphanumeric:
^[a-zA-Z0-9]+$- Matches only letters and numbers.
Frequently Asked Questions (FAQ)
- What is Regular Expression (RegEx)?
- A Regular Expression constitutes a sequence of characters that specifies a search pattern. It is commonly used for string searching, manipulation, and validation.
- Is this tool compatible with all programming languages?
- This tool uses the JavaScript RegExp engine. While most RegEx syntax is standard across languages (like Python, Java, PHP), there might be slight variations in advanced features.
- How do I validate an email address?
- You can use a pattern like
^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$to validate standard email formats. - Does this tool support lookbehind?
- Yes, modern JavaScript engines (including this tool running in your browser) support positive and negative lookbehind assertions.