Architect a scalable React frontend for an enterprise SaaS platform

Interview framing: For a senior role, show that architecture is about boundaries, change tolerance, and observability, not only folder structure.

Architecture approach:

1. Feature boundaries:

• Organize by product domain: policies, identities, resources, decisions, audit, admin.
• Keep feature-specific components, hooks, and API calls close together.
• Put only truly reusable primitives in a shared layer.

2. Routing and layout:

• Use route-level loading/error states.
• Keep tenant, workspace, and environment selection explicit in the URL or app shell.
• Protect routes in the frontend for UX, but enforce permissions on the backend.

3. State management:

• Server data should live in a query/cache layer.
• Local UI state belongs near the component.
• Complex form/workflow state can use reducers or state machines.

4. API boundary:

• Centralize auth headers, error normalization, retries, cancellation, and tracing IDs.
• Validate important response shapes at runtime when data is security-sensitive.

5. Performance:

• Code-split large routes.
• Virtualize large tables.
• Memoize expensive policy/resource transformations.
• Measure slow interactions with real production-like data.

6. Testing:

• Unit-test pure logic and permission helpers.
• Component-test forms, tables, and policy builders.
• Add focused E2E tests for critical tenant and policy workflows.

Strong closing: "I would optimize the architecture for product teams to ship independently while keeping auth, audit, error handling, and design-system behavior consistent across the platform."