What are 'functional requirements'?

Functional requirements define the specific behavior and functions of a system, essentially outlining what the system must do to meet the needs of its users and stakeholders. These requirements specify the interactions that occur between users and the system, including the inputs, processes, and outputs involved. They often detail user interactions, business rules, and the essential features that must be implemented for the system to operate correctly.

For example, a functional requirement may specify that a user must be able to log in to a system, submit a form, or generate a report. This emphasis on system capabilities and user interactions establishes a clear framework for the development and testing of the system's functionalities.

Other choices focus on aspects that don't encapsulate the definitive aspect of functional requirements. While they address important components of a system's overall design and performance, they do not specifically align with the core definition of functional requirements.