State Management Guide for React Applications

State is data that changes over time and affects what your application renders. React provides several built-in tools for managing state, and the ecosystem offers many more. Choosing the right state management approach depends on the scope of your state, how often it changes, and how many components need access to it. The most common mistake is reaching for complex state management libraries when React's built-in tools would suffice.

For state that belongs to a single component or a small component tree, `useState` is the simplest and best choice. Use it for form inputs, toggle states, and local UI state. When state logic becomes complex with multiple related values, switch to `useReducer`, which manages state transitions through a reducer function. Keep state as local as possible and lift it up only when sibling components need to share it. This principle alone prevents many state management headaches.

Data fetched from your API is server state, not client state, and should be managed differently. Libraries like TanStack Query and SWR handle caching, background refetching, optimistic updates, and error states automatically. They eliminate the need to manually store API responses in global state. Using these libraries typically removes half or more of your global state management needs. If you are storing API responses in Redux or Zustand, consider migrating to a dedicated server state library instead.

React's Context API lets you share state across your entire component tree without prop drilling. It works well for infrequently changing data like user authentication, theme preferences, and locale settings. However, Context re-renders every consumer when the provided value changes, which can cause performance issues with frequently changing data. Split your contexts by concern so that a theme change does not re-render components that only care about authentication.

When Context API's performance limitations become an issue, lightweight libraries like Zustand and Jotai offer better alternatives. Zustand provides a simple store with selective subscription, so components only re-render when the specific data they use changes. Jotai uses an atomic approach where each piece of state is an independent atom. Redux remains popular for large applications but adds significant boilerplate. For most AI-built applications, Zustand offers the best balance of simplicity and power.

Search filters, pagination, and other shareable application state should live in the URL. When a user shares a link or refreshes the page, the application state should be preserved. Use URL search parameters for filter states and path parameters for resource identification. Libraries like nuqs for Next.js make managing URL state easy. Keeping shareable state in the URL improves user experience and is essential for SEO on content pages.

AI-generated React applications frequently misuse state management, storing everything in global state, duplicating server data in client stores, or creating deeply nested prop drilling chains. This leads to unnecessary re-renders, stale data bugs, and code that is difficult to maintain. SpringCode refactors state management in AI-built React apps, moving server state to proper data fetching libraries, localizing component state, and implementing efficient global state patterns.