What is a Regular Expression (Regex)?
A Regular Expression is a sequence of characters that specifies a search pattern in text. Regex is incredibly powerful for string searching, text validation (like checking if an email is formatted correctly), and advanced find-and-replace operations. It is universally used in programming languages like JavaScript, Python, Java, and PHP.
Regex Tester FAQ
Which flavor of Regex does this tool use?
This tool utilizes the native JavaScript (ECMAScript) Regex Engine. It supports most standard regex features including capturing groups, lookaheads, and character classes, making it highly compatible for web developers.
Is my tested text kept private?
Yes. Many developers need to test regex against sensitive logs or customer data. Our Regex Tester executes the search pattern completely inside your browser using client-side JavaScript. Your text and patterns are never uploaded to any server.