Designing a robust application requires systematic planning across multiple phases to balance user needs, technical feasibility, and long-term maintainability. This checklist groups essential steps, drawing from industry best practices to help teams deliver scalable, secure software efficiently.

Requirements Gathering

Start with a solid foundation by capturing what the application must achieve. Clear requirements prevent costly pivots later.

  • Identify all stakeholders, including end-users, business owners, and compliance teams, through structured interviews or workshops.
  • Create detailed user personas and map core journeys, including edge cases like offline access or high-volume usage.
  • Document functional requirements as user stories with acceptance criteria (e.g., "As a user, I can upload files up to 50MB").
  • Outline non-functional specs: performance targets (e.g., page load <2s), scalability (handle 10k concurrent users), and reliability (99.99% uptime).
  • Prioritize using frameworks like MoSCoW (Must-have, Should-have, Could-have, Won't-have) or a value-effort matrix.
  • Analyze constraints such as budget, timeline, legal requirements (e.g., data sovereignty in NZ), and integration needs.

Architecture Design

Architecture sets the blueprint for scalability and evolution. Evaluate options against your specific stack, like Java/Spring on AWS.

  • Decide on style: monolithic for simplicity, microservices for scale, or serverless for cost efficiency.
  • Select technologies: backend (Spring Boot 3.3+), frontend (React/Vue), databases (relational like PostgreSQL or NoSQL like MongoDB).
  • Design components: data schemas, APIs (RESTful or GraphQL), event-driven patterns (Kafka for async processing).
  • Plan for growth: auto-scaling groups, caching layers (Redis), CDNs, and containerization (Docker/Kubernetes).
  • Incorporate observability from day one: logging (ELK stack), metrics (Prometheus), tracing (Jaeger).
  • Review trade-offs: weigh development speed against operational complexity.

UI/UX Design

A intuitive interface drives adoption. Focus on empathy and iteration for seamless experiences.

  • Develop low-fidelity wireframes progressing to interactive prototypes (tools like Figma or Sketch).
  • Ensure cross-device responsiveness and accessibility (WCAG compliance: screen reader support, keyboard navigation).
  • Detail user flows: onboarding, navigation, error handling with clear messaging.
  • Validate with usability tests: A/B variants, heatmaps, and feedback from 5-8 target users.
  • Maintain design system consistency: tokens for colors, spacing, typography; subtle animations for delight.
  • Optimize for performance: lazy loading, optimized assets.

Security and Compliance

Security is non-negotiable—build it in, don't bolt it on. Anticipate threats proactively.

  • Conduct threat modeling using STRIDE (Spoofing, Tampering, etc.) to identify risks.
  • Implement identity management: multi-factor auth, role-based access (OAuth2/OpenID via AWS Cognito).
  • Protect data: encryption (TLS 1.3, AES-256), secure storage, input sanitization against XSS/SQLi.
  • Automate scans: vulnerability checks (SonarQube), secrets detection, dependency audits.
  • Align with regulations: privacy by design, audit trails for traceability.

Testing and Deployment

Rigorous testing and smooth deployment ensure reliability in production.

  • Structure tests: 70% unit/integration (JUnit, pytest), 20% system, 10% exploratory/manual.
  • Automate pipelines: CI/CD with GitHub Actions/Jenkins for build, test, deploy stages.
  • Stress-test: load simulations (Locust), chaos engineering (fault injection).
  • Prepare deployment: blue-green rollouts, feature flags, monitoring dashboards (CloudWatch/Grafana).
  • Post-launch: incident response plan, user analytics, iterative feedback loops.