--- title: use client description: Learn how to use the use client directive to render a component on the client. --- The `'use client'` directive declares an entry point for the components to be rendered on the **client side** and should be used when creating interactive user interfaces (UI) that require client-side JavaScript capabilities, such as state management, event handling, and access to browser APIs. This is a React feature. > **Good to know:** > > You do not need to add the `'use client'` directive to every file that contains Client Components. You only need to add it to the files whose components you want to render directly within Server Components. The `'use client'` directive defines the client-server [boundary](https://nextjs.org/docs/app/building-your-application/rendering#network-boundary), and the components exported from such a file serve as entry points to the client. ## Usage To declare an entry point for the Client Components, add the `'use client'` directive **at the top of the file**, before any imports: ```tsx filename="app/components/counter.tsx" highlight={1} switcher 'use client' import { useState } from 'react' export default function Counter() { const [count, setCount] = useState(0) return (

Count: {count}

) } ``` ```jsx filename="app/components/counter.js" highlight={1} switcher 'use client' import { useState } from 'react' export default function Counter() { const [count, setCount] = useState(0) return (

Count: {count}

) } ``` When using the `'use client'` directive, the props of the Client Components must be [serializable](https://react.dev/reference/rsc/use-client#serializable-types). This means the props need to be in a format that React can serialize when sending data from the server to the client. ```tsx filename="app/components/counter.tsx" highlight={4} switcher 'use client' export default function Counter({ onClick /* ❌ Function is not serializable */, }) { return (
) } ``` ```jsx filename="app/components/counter.js" highlight={4} switcher 'use client' export default function Counter({ onClick /* ❌ Function is not serializable */, }) { return (
) } ``` ## Nesting Client Components within Server Components Combining Server and Client Components allows you to build applications that are both performant and interactive: 1. **Server Components**: Use for static content, data fetching, and SEO-friendly elements. 2. **Client Components**: Use for interactive elements that require state, effects, or browser APIs. 3. **Component composition**: Nest Client Components within Server Components as needed for a clear separation of server and client logic. In the following example: - `Header` is a Server Component handling static content. - `Counter` is a Client Component enabling interactivity within the page. ```tsx filename="app/page.tsx" highlight={2,8} switcher import Header from './header' import Counter from './counter' // This is a Client Component export default function Page() { return (
) } ``` ```jsx filename="app/page.js" highlight={2,8} switcher import Header from './header' import Counter from './counter' // This is a Client Component export default function Page() { return (
) } ``` ## Reference See the [React documentation](https://react.dev/reference/rsc/use-client) for more information on `'use client'`.