Non-functional requirements (NFRs) define the quality attributes of a system, such as performance, security, and usability.

Explanation:

• NFRs focus on how a system works, not what it does.
• Types:
  • Performance – “The system should handle 10,000 concurrent users.”
  • Security – “User data must be encrypted using AES-256.”
  • Usability – “Users should complete checkout in less than 3 steps.”

Example:

For a banking app, an NFR could be:

• “Transactions should be completed within 2 seconds.”