●React + SaaS

React dominates SaaS frontend development for a simple reason: the ecosystem has solved every common problem. Data tables, forms, charts, real-time updates, permission systems—there are mature, maintained solutions for each. You're not building infrastructure; you're composing battle-tested solutions into your specific product. The component model maps naturally to SaaS concepts. A Dashboard is composed of Widgets. Widgets contain Charts or Tables. Tables have Rows with Actions. Each component manages its own data fetching, loading states, and error handling. This composability means features can be developed in isolation and assembled into pages without creating a tangled dependency graph. React 18's concurrent features address the performance challenges unique to SaaS interfaces. When a user triggers a heavy operation—generating a report, filtering a large dataset, importing records—the UI remains responsive. React automatically yields to user interactions, preventing the frozen UI that makes applications feel broken. This isn't optional polish; it's the baseline expectation for professional software. For B2B SaaS specifically, React's testing story is essential. React Testing Library encourages tests that verify user behavior, not implementation details. When your enterprise customer asks 'how do you ensure data exports work correctly,' you can point to tests that actually click the export button and verify the file download—not mocked unit tests that might drift from reality.

SaaS frontend architecture requires thinking in systems, not pages. I start by mapping the data model: What entities exist? How do they relate? What operations can users perform? This produces a mental model that guides component architecture. React components mirror the domain model, making the codebase navigable for future developers. The data layer comes next. React Query handles all server state—customer data, subscription status, feature flags, analytics. Each query has explicit caching rules, refetch triggers, and error handling. Mutations implement optimistic updates where appropriate, giving users instant feedback while operations complete server-side. The pattern is consistent across the entire application. For UI architecture, I build from a design system. Whether using shadcn/ui as a starting point or implementing a custom system, the goal is consistency and accessibility. Every interactive element has proper focus states, keyboard navigation, and ARIA attributes. Enterprise customers increasingly require WCAG 2.1 AA compliance, and building accessibility in from the start is vastly cheaper than retrofitting. Feature flags and permissions are infrastructure, not afterthoughts. I implement FeatureGate and PermissionGate components early, even if the initial product has simple access control. When you need to gate a premium feature or roll out gradually, the patterns are already in place. Testing focuses on user flows, not component internals. A test suite that verifies 'user can invite team member' is more valuable than tests verifying internal state changes. These integration tests catch regressions that unit tests miss while serving as documentation for how features should behave.