Regex Tester

Regex Tester is a web-based regular expression debugging tool built with native JavaScript, supporting real-time matching, highlight display, syntax explanation, and test case management.

Main Features

• Real-time matching: Enter regex pattern and test string, view matches instantly
• Highlight display: Matched content highlighted in the original text
• Syntax explanation: Automatically explains each part of the regex
• Multi-flag support: Supports g/i/m/s/u and other common flags
• Test cases: Add multiple test cases for batch validation
• Common patterns: Built-in patterns for email, URL, phone, IP address
• Capture group display: Clearly shows content of each capture group

How to Use

1. Enter a pattern in the regex input field (e.g., \d+)
2. Enter text to match in the test string field
3. Select desired matching flags
4. View real-time highlighted results and match details
5. Use “Common Patterns” to quickly insert frequently used regex

Technical Features

• Pure frontend implementation, no backend required
• Based on browser native RegExp API
• Supports all major regex syntax
• Responsive design for desktop and mobile

Use Cases

• Writing form validation regex in frontend development
• Data cleaning and extraction rule debugging
• Regex learning and teaching
• Combine with JSON tools for structured data processing

Last verified: 2026-04-07 Source: SunneV/OpenRegex