NFRs define how well the system must perform—covering performance, scalability, availability, security, UX quality, and other operational expectations.
Purpose and Benefits
- Performance & reliability: Measurable targets for speed and stability.
- Architecture planning: Guides capacity, scaling, and infrastructure design.
- Security & compliance: Sets encryption, auth, and audit baselines.
- User experience: Ensures responsiveness and accessibility.
- Operational resilience: Drives DR, monitoring, and risk reduction.
- Testability: QA and DevOps can validate against concrete thresholds.
Recommended Non-Functional Requirements Template
| Category | Details |
|---|---|
| Performance | 1. App cold ≤ 2s; warm ≤ 500ms. 2. Payment flow P95 ≤ 1.5s. 3. API latency P95 ≤ 300ms, P99 ≤ 1s. 4. Local wallet ops P95 ≤ 100ms. 5. Throughput 200 RPS sustained. |
| Scalability | 1. Support up to 100,000 concurrent active users. 2. Horizontal autoscaling for services. 3. Storage scales to 100M wallet records. 4. Worker queues scale dynamically for payments. |
| Availability | 1. Uptime ≥ 99.95% monthly. 2. Critical payment services ≥ 99.9%. 3. DR RTO ≤ 1h, RPO ≤ 15m. 4. Graceful degradation keeps core payments running. |
| Security | 1. MFA with biometrics + PIN. 2. RBAC for admin access. 3. TLS 1.2+ in transit, AES-256 at rest. 4. Keys via KMS/HSM with rotation. 5. Audit logs retained ≥ 1 year. 6. Fraud detection rules for suspicious transactions. |
| Usability & UX Quality | 1. Primary payment flow ≤ 3 steps. 2. Success/failure feedback ≤ 1s. 3. First-time setup ≤ 5 minutes. 4. WCAG 2.1 AA compliance. 5. Localization for currency, date, time, and multiple languages. |
| Other Requirements | 1. Push notification delivery P95 ≤ 5 seconds. 2. Telemetry collection <1% overhead. 3. PCI-DSS compliance for card transactions. 4. Audit/compliance reports on demand. |
Field Explanation
- Category: Performance, Scalability, Availability, Security, Usability, Reliability, Compliance, etc.
- Details: Specific, measurable, testable expectations for the category.