Hire React.js Developers

Many production apps still run on React 16 or 17, class components, and Create React App, which the React team deprecated in 2025. We upgrade them to the current React in stages, and your team keeps shipping while the work is in progress.

• Upgrade Assessment. We inventory class components, remove APIs such as ReactDOM.render, string refs, and legacy context, and identify the libraries that block the upgrade. You get a plan with effort per module and a list of dependencies to replace.
• Create React App to Vite or Next.js. We move the build off react-scripts to Vite for single-page apps, or to Next.js where you need server rendering. The dev server starts in seconds, and the toolchain is supported again.
• Class Components to Hooks. Lifecycle methods and higher-order components are rewritten as function components and custom hooks, starting with the code your team changes most often. The codebase gets smaller and easier to test.
• State Management Cleanup. Hand-written Redux reducers and thunks move to Redux Toolkit, and server data moves to TanStack Query. Most of the boilerplate goes away, and caching stops being custom code.
• Enzyme to React Testing Library. Enzyme has no official adapter for React 18 and later, so we rewrite those tests with React Testing Library. The new tests check what users see rather than component internals, so they survive refactoring.

Our developers build customer portals, admin panels, and B2B SaaS front ends with React, TypeScript and a deliberately small set of proven libraries. They connect the UI to your existing APIs, whether the back end runs on .NET, Node.js, Java, Python, or PHP.

• Customer Portals. Self-service areas for accounts, orders, invoices, and support requests. Customers handle routine tasks without contacting your team.
• Data-Heavy Dashboards. Tables with server-side sorting, filtering, and pagination built on TanStack Table, plus charts and bulk actions. Operations teams work with tens of thousands of records without exporting to Excel.
• Complex Forms. Multi-step forms, conditional fields, and validation with React Hook Form and Zod, using the same schema on the client and the server. Users get instant feedback, and invalid data never reaches the API.
• Typed API Layer. TypeScript clients generated from your OpenAPI or GraphQL schema, with TanStack Query handling caching, retries, and optimistic updates. An API change breaks the build, not production.
• Authentication and Role-Based UI. Sign in through your identity provider via OIDC or SAML, with routes and actions gated by role and feature flags. The UI mirrors your server-side permissions from one place instead of scattered checks across components.

For public pages and content-heavy products, we build with Next.js and choose the rendering mode per route: static, incrementally regenerated, or server-rendered on each request.

• App Router and Server Components. Data fetching moves to the server, and only interactive parts of the page ship JavaScript to the browser. Pages load faster, and API keys stay off the client.
• Pages Router to App Router Migration. Both routers run side by side in one app, so we migrate route by route instead of in one release. Your team keeps shipping features throughout.
• Caching and Revalidation. We set caching rules per route and per data source, with on-demand revalidation when content changes. Editors see updates within seconds, and your origin isn’t hit on every request.
• SEO Foundation. Metadata, structured data, canonical URLs, sitemaps, and Open Graph images generated from your content. Search engines index pages correctly from the first release.
• Headless CMS and Hosting. Next.js connected to Contentful, Sanity, Strapi, or Storyblok with draft preview, deployed to Vercel or self-hosted on AWS or your own Kubernetes. Self-hosting keeps you free of platform lock-in when pricing or compliance requires it.

For products built on AngularJS, jQuery, Backbone, or server-rendered templates, we replace the front end with React one section at a time. Old and new code run side by side until the move is complete.

• Front-End Inventory. We map every page, script, and dependency in the old front end and rank them by traffic and risk. You see what to migrate first and what you can retire.
• React Islands in Legacy Pages. We mount React components inside existing pages, so new features ship in React while the old shell keeps working. Nothing waits for the full rewrite.
• Route-by-Route Migration. Pages move to React one route at a time behind a shared navigation and session. Users see one product throughout the move.
• Micro-Frontends Where They Pay Off. When several teams own separate areas of the product, we split the front end with Module Federation so each team releases independently. For a single team, we usually advise against it, because the extra complexity costs more than it saves.
• Visual Regression Testing. Automated screenshot comparisons run on every change between old and new pages. Layout and behavior differences are caught before release.

We turn your Figma design system into a library of typed, documented React components. Product teams build screens from the same tested parts, and a design change reaches every product from one place.

• Design Tokens. Colors, spacing, typography, and themes exported from Figma and converted into tokens and CSS variables. Rebranding or adding dark mode becomes a change in one file.
• Components on Headless Primitives. Components built on Radix UI or React Aria, which handle focus, keyboard, and ARIA behavior. Your team styles the components instead of reinventing dropdowns and dialogs.
• Storybook Documentation. Every component documented with live examples, props and usage rules, plus interaction and visual tests. Designers and developers work from the same reference.
• Accessibility to WCAG 2.2 AA. Keyboard navigation, focus management, screen reader labels, and contrast are checked for each component. Every screen built from the library inherits compliance.
• Versioned Package Publishing. The library is published as a private npm package with semantic versioning, changelogs, and codemods for breaking changes. Product teams upgrade on their own schedule without manual rewrites.

We profile the app with React DevTools and real-user data, measured against Core Web Vitals. Special attention goes to Interaction to Next Paint (INP), which replaced FID in 2024 and is often the weakest metric in client-heavy React apps.

• Performance Audit. Lab tests and field data are combined into a ranked list of bottlenecks, each with its expected impact. You fix what matters first instead of guessing.
• Re-render Fixes. We find components that re-render without reason and fix them through state colocation, memoization where measurements justify it, or React Compiler where the codebase follows the Rules of React. Typing, scrolling, and filtering stay smooth.
• Bundle and Hydration Cost. Code is split by route with React.lazy and dynamic imports, heavy dependencies are replaced, and static parts move to Server Components. Users download and hydrate less JavaScript on first load.
• Responsive Interactions. Heavy updates run through useTransition and useDeferredValue, and long lists are virtualized. Input responds immediately while results render in the background.
• Performance Budgets in CI. Bundle size and Lighthouse thresholds are checked on every pull request. Regressions are caught before they reach production.

A senior React developer reviews your codebase for architecture, state management, security, and test coverage. You get a prioritized list of findings with recommended fixes, which your team or ours can then address.

• Architecture Review. We assess folder structure, component boundaries, and coupling between features. You see where the codebase resists change and why.
• State and Effects Review. We look for useEffect used to sync or derive state, race conditions in data fetching, and server data duplicated in global stores. These patterns cause most stale-data bugs and unnecessary renders in React apps.
• Security Review. We check for unsanitized dangerouslySetInnerHTML, tokens kept in localStorage, secrets exposed through public environment variables, and vulnerable dependencies. Each finding comes with a severity rating and a fix.
• Test Coverage Analysis. We measure what the tests cover and which critical flows have no tests at all. You know where a change is likely to break something unnoticed.
• Remediation Roadmap. All findings are combined into a prioritized plan with effort estimates. Your team or ours can start on it the next sprint.

Developers cover business logic and components with Vitest or Jest and React Testing Library, and critical flows with Playwright. After launch, the same team handles bug fixes, dependency updates, and new features.

• Unit and Component Tests. Components are tested the way users interact with them, with API calls mocked at the network level through MSW. Tests stay valid when internals change.
• End-to-End Tests. Critical flows such as sign-up, checkout, and payments are automated with Playwright across browsers. Releases are checked the way customers actually use the product.
• CI Quality Gates. ESLint with React Hooks rules, strict TypeScript checks, and tests run on every pull request. Broken code is blocked before merge.
• Dependency and Security Updates. React, Next.js and third-party packages are updated on a regular schedule, and vulnerabilities are patched as advisories come out. The app stays on supported versions.
• Feature Development. The developers who already know your codebase build new features and improvements. You don’t onboard a new team for every change.