hydration-safety

Fix Next.js hydration mismatches by adding 'use client' to components accessing browser APIs and implementing the isMounted pattern with useEffect to delay client-only rendering until after mount.

Next.js SSR throws hydration errors with localStorage because the server cannot access browser APIs, causing a mismatch between server-rendered HTML and client output. Use conditional rendering and the isMounted pattern to keep them in sync.

The best way to use the window object in Next.js client-side rendering is applying the isMounted pattern via useEffect, ensuring window access only occurs post-mount to align SSR and client hydration output.

Prevent hydration errors for time-based UI components in Next.js by using 'use client' and conditional rendering with the isMounted pattern, ensuring dynamic client-only features align server and client renders across routes.

Yes, you can use useEffect to delay browser API access during Next.js SSR by implementing the isMounted pattern, which defers dynamic client-only features until after the component mounts to prevent hydration mismatches.

You need 'use client' for Next.js hydration safety when a component accesses browser-only APIs like window or localStorage, requiring the isMounted pattern and safe defaults to prevent runtime hydration mismatches.