Web App Development
React Web App Development With a Server-First Architecture
We build React web apps that go beyond client-side rendering — Server Components for performance, TypeScript for safety, and state architecture that does not collapse at scale.
React Web App Development Done Right, Not Just Fast
React has been the dominant UI library for a decade, but that familiarity has generated an ecosystem of cargo-culted patterns that slow development and create technical debt. useEffect as a data-fetching mechanism, excessive prop drilling through five component layers, and global Context providers for state that three components share — these are the React antipatterns we find in almost every inherited codebase. We build React web apps with the architectural discipline React's own team recommends: server rendering first, client interactivity second, state kept as local as possible.
React state management is the question that starts more architecture debates than any other in web development. Redux, Zustand, Jotai, React Query, SWR — each solves a different problem, and reaching for a global state manager before you have genuinely outgrown local state is the most common over-engineering mistake in React web app development. We assess your actual data flow requirements before choosing any state architecture. The answer is almost always React Query for server state, useState for UI state, and nothing else until the project proves it needs more.
React performance optimization is widely misunderstood. Most developers reach for useMemo and useCallback to 'prevent re-renders' without measuring whether those re-renders are actually expensive. The real React performance levers are: moving data fetching to the server, keeping state as close as possible to where it is used, virtualizing large lists, and avoiding unnecessary JavaScript on the client. We build React web apps that are performant by architecture, not by patch — so there is no optimization sprint needed after launch.
Our Approach to React web app development
Every project follows our 4-step vibe-coding process — AI handles the boilerplate, senior engineers handle the craft. From idea to live product in 3–7 days for MVPs.
Discovery
We map your data requirements — which data is static, which changes on user action, which needs real-time updates — and design the component architecture before writing code. In Next.js with React, this means identifying which components are Server Components (zero client JavaScript) and which genuinely need client-side interactivity.
Design
We design component hierarchies that minimize state and maximize server rendering. Every UI element is evaluated: does this need client-side state, or can it be a server-rendered component? We create a component inventory during design that guides the build phase and prevents the 'make it a client component' shortcut that inflates bundle sizes.
Build
React 19 with Server Components via Next.js App Router, TypeScript strict mode, React Query for server-state synchronization in client components, Tailwind CSS for utility-first styling, and Zod for runtime validation of API responses. AI generates component scaffolding; our engineers make every architectural boundary decision and review every component for unnecessary client-side state.
Launch
Bundle analysis before deployment: we run Next.js bundle analyzer to identify any unexpectedly large client-side chunks and eliminate unnecessary client JavaScript. Lighthouse audit on every key page. We configure React Error Boundary components at critical user flows so a JavaScript error in one feature does not crash the entire application.
What You Get
Every react web app development engagement includes these deliverables — scoped before we start, delivered before we invoice.
- React 19 component library built with Tailwind CSS and typed props throughout
- Server Components for all data-fetching views — zero client JavaScript for initial render
- Client Components isolated to interactive elements with explicit 'use client' boundaries
- TypeScript strict mode with Zod schemas for runtime API response validation
- React Query setup for all server-state data fetching in client components
- Error Boundary components at all critical user flow boundaries
- Custom hooks extracted for reusable stateful logic with full TypeScript typing
- Bundle analysis report and optimization — client JavaScript under 200kb for initial load
- Accessibility audit: ARIA labels, keyboard navigation, and focus management
- Storybook or component documentation for UI components (optional, scoped separately)
Tech Stack We Use
React web app development at Greta is built on React 19 via Next.js 15, which provides the Server Component runtime that makes React genuinely performant at scale. We use TypeScript in strict mode for type-safe component props and hook signatures, Tailwind CSS for consistent styling without CSS-in-JS bundle overhead, React Query for server-state data fetching in client components, and Zod for runtime validation of all external data — API responses, form inputs, URL params. For real-time features, we use Supabase real-time subscriptions with React's useEffect cleanup to prevent subscription memory leaks. Every component renders correctly in server-side rendering context before we add any client-side behavior.
Case Study
PLGOS — React Dashboard With Real-Time Data
PLGOS required a React dashboard that displayed real-time activation event data across multiple user accounts — a genuinely complex client-side rendering challenge. We built the dashboard with Next.js Server Components for the initial data load (fast first render, no loading spinner), React Query for subsequent data refreshes, and Supabase real-time subscriptions for the live event feed. Each dashboard component was audited for unnecessary client-side state — several components that initially had client-side data fetching were converted to Server Components, reducing the client JavaScript bundle by 38%. The dashboard handled 340 concurrent users at peak load without performance degradation.
Read full case studyPricing Transparency
React web app development starts at $5,000 for MVP-scoped applications. Complex single-page applications with rich interactivity, real-time features, and large component libraries run $15,000–$40,000. Pages Router to App Router migrations, or Create React App to Next.js migrations, are scoped after a codebase audit. All projects include a bundle analysis report and Core Web Vitals audit before handoff.
MVP
From $5,000
3–7 business days
Full Build
From $15,000
2–4 weeks
All projects include full code ownership, two revision rounds, Vercel deployment, and one week of post-launch support. No hidden fees.
Frequently Asked Questions
Do you build React SPAs or server-rendered apps?
We build server-rendered React apps via Next.js App Router. Pure client-side SPAs with Create React App are a pattern we have moved away from entirely — they have worse initial load performance, worse SEO, and worse data fetching ergonomics than server-rendered alternatives. If you have a CRA project, we can migrate it to Next.js.
How do you decide which components are Server vs Client Components?
The rule we use: a component is a Server Component by default. It becomes a Client Component only if it needs useState, useEffect, browser APIs, or event handlers. Data fetching is never a reason to use a Client Component in App Router — Server Components fetch data more efficiently. We enforce this rule in code review on every PR.
What state management library do you use?
For server state (data fetched from APIs), we use React Query. For UI state (modals, form inputs, toggle state), we use useState and useReducer. We add Zustand only when multiple distant components genuinely need shared client-side state without a server-state solution. We never add Redux to a new project in 2025.
How do you handle forms in React?
We use React Hook Form for complex forms with validation — it is the most performant form library because it avoids re-rendering on every keystroke. For simpler forms, we use Server Actions in Next.js App Router, which handle form submission without client-side JavaScript entirely. Zod schemas validate all form data on both client and server.
What is your approach to React accessibility?
Every interactive element has an accessible label. Focus management is handled in modal and dialog components. Keyboard navigation works for all interactive UI. We use Radix UI primitives for complex components like dropdowns, modals, and tooltips because they have accessibility built in — we do not rebuild these from scratch.
Can you optimize an existing React app that is performing poorly?
Yes. We offer a React performance audit: bundle analysis, render profiling with React DevTools Profiler, and identification of the specific components causing performance issues. The audit produces a prioritized list of optimizations. Most React performance problems we find are the same three: unnecessary re-renders from unstable references, large unvirtualized lists, and client-side data fetching that should move to the server.
How do you handle real-time data in React?
For real-time data, we use Supabase real-time subscriptions. In React, every subscription opened in useEffect must have a cleanup function that unsubscribes when the component unmounts — missing cleanup causes memory leaks and duplicate event handlers. We audit every subscription in our code review process specifically for this pattern.
Do you write React component tests?
We write end-to-end tests for critical user flows using Playwright, which tests the full application behavior. For complex component logic — state machines, form validation, data transformation — we write unit tests with Vitest. We do not test every component in isolation; the overhead rarely pays for itself on early-stage products.
Ready to ship?
Ready to build your React web app?
Start Your ProjectOr reach us directly at hello@greta.agency
Written by the Greta Agency team · Last updated April 2025