What is the main difference between static and dynamic testing?

The main difference between static and dynamic testing is that dynamic testing involves executing the software, whereas static testing does not involve any execution of the software at all. Dynamic testing is performed on software that is running, allowing testers to interact with it and observe its behavior in real-time. This helps in identifying issues such as functional defects, performance problems, and user interface challenges during runtime.

On the other hand, static testing is conducted through techniques such as reviews and inspections of the code, documentation, and other project artifacts without running the software. This approach is typically employed early in the development lifecycle and focuses on finding issues related to code quality and compliance with requirements. By not executing the software, static testing can identify defects early in the development process, potentially leading to reduced costs and improved efficiency later on.

This distinction helps testers understand when and how to apply different testing techniques to ensure a comprehensive evaluation of the software's quality throughout its development lifecycle.