Nonfunctional requirements are the criteria that define how a system should perform, rather than what the system should do.

These requirements focus on the quality attributes of a software system, such as performance, security, reliability, scalability, and usability.

Nonfunctional requirements are essential for ensuring that a software system meets the needs and expectations of its users. Nonfunctional requirements are often overlooked or underestimated in software development, but they play a crucial role in the success of a project.

They help to define the overall quality of a software system and are key to ensuring that the system meets the needs of its users.

Nonfunctional requirements are typically more difficult to measure and test than functional requirements, but they are just as important for the overall success of a project. Nonfunctional requirements can be classified into various categories, such as performance requirements, security requirements, reliability requirements, and usability requirements.

Performance requirements define how well the system should perform under certain conditions, such as response time, throughput, and resource usage.

Security requirements define how the system should protect sensitive data and prevent unauthorized access.

Reliability requirements define how reliable the system should be in terms of availability, fault tolerance, and recovery.

Usability requirements define how easy and intuitive the system should be to use. In conclusion, nonfunctional requirements are essential for defining the quality attributes of a software system and ensuring that the system meets the needs and expectations of its users.

By paying attention to nonfunctional requirements, software developers can create systems that are not only functional but also reliable, secure, and user-friendly.