🔍 正規表現テスター

Free Online Regex Tester — Test and Debug Regular Expressions

Our regex tester lets you write and test regular expressions in real time. Enter your regex pattern and test text, and instantly see all matches highlighted. Choose from common flags (global, case-insensitive, multiline) and get detailed match information including match position and capture groups.

Regular expressions are a powerful tool for text pattern matching used in programming, data validation, search-and-replace, and text extraction. Whether you're a developer debugging a regex pattern, a data analyst extracting information from logs, or a student learning regex syntax, our tester provides instant visual feedback. すべてローカル処理.

Key Features

Real-time matching — See matches highlighted instantly as you type
Flags support — Toggle global, case-insensitive, and multiline flags
Match details — Shows match position, count, and capture groups
Clear error messages — Get helpful feedback on invalid regex patterns
100% private — All processing in your browser — zero uploads

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