What Is a Client Component?

A client component is a component explicitly marked to run in the browser, where its JavaScript is downloaded and executed. It can hold local state, run effects, and attach event handlers, which server components cannot. The cost is the bundle weight and hydration its interactivity requires.

Why it matters

Client components provide the interactivity a page needs, but each one adds to the JavaScript the browser must load. Limiting them to genuinely interactive parts keeps bundles lean.

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