What non-functional requirements have you had to address?

Non-functional requirements I had to work with include:

• Performance: defining the maximum system response time and throughput.
• Reliability and fault tolerance: ensuring uninterrupted operation, redundancy, and recovery after failures.
• Security: requirements for authentication, authorization, data encryption.
• Scalability: the ability to increase load without loss of quality.
• Maintainability: logging, monitoring, the ability to quickly fix errors.

For example, when developing a corporate portal, we set an SLA for response time of no more than 2 seconds with 1000 concurrent users, as well as requirements for encrypting personal data in accordance with GDPR.