What non‑functional requirements and questionnaires do you need to ask the client?

Non‑functional requirements (NFRs) for performance testing typically include response time, throughput, concurrency, scalability, reliability, availability, and resource utilization. To gather these from the client, I use a structured questionnaire covering: 1) Business goals – what is the critical success factor? 2) Expected user load – peak concurrent users, transaction volume per hour. 3) Performance targets – acceptable response times for key transactions. 4) Scalability expectations – how many users should the system support in the next 2‑3 years? 5) Reliability and availability – required uptime percentage and mean time between failures. 6) Environmental constraints – hardware, network bandwidth, and third‑party services. 7) Security and compliance – any specific performance impact from encryption or audit logging. 8) Maintenance windows and rollback procedures. The questionnaire is tailored to the domain (e.g., banking, e‑commerce) and ensures that the test plan aligns with business expectations.