Regex Tester

Regular expressions are powerful but unforgiving — a single character can change a pattern that matches everything into one that matches nothing. This regex tester gives you a live workspace to build and refine patterns against real sample text, with matches highlighted as you type. Capture groups are listed separately so you can verify your pattern is extracting the right substrings, and the most common flags (global, case-insensitive, multiline) are toggled with a single click.

Practical uses include writing input validation rules, building search-and-replace expressions for refactoring large code bases, parsing structured logs, and extracting data from semi-structured text. Because the testing happens in your browser, you can confidently work with private data — production logs, customer records, internal documents — without anything leaving your machine.