What is 正規表現テスター?

A tool for testing regular expressions with real-time matching against test strings. Used for debugging and developing regex patterns for string searching, validation, and text parsing in development workflows.

How to Use

1. Enter your regex pattern in the top input field.
2. Enter the test string in the area below.
3. Matching portions are highlighted in real-time.
4. Configure flags (case insensitive, multiline, etc.) to adjust matching behavior.

Key Features

• Real-time regex matching with highlighting
• Case insensitive, multiline, and dotAll flags
• Detailed match text, position, and capture group display
• ECMAScript, RE2, and PCRE2 engine selection

Tips

• For email validation, use standardized regex patterns rather than simple ones.
• Capture groups () allow you to extract specific matched portions.
• Using the ? quantifier performs lazy (non-greedy) matching instead of the default greedy matching.