| --- | |
| title: Rendering | |
| description: Learn the fundamentals of rendering in React and Next.js. | |
| --- | |
| By default, Next.js **pre-renders** every page. This means that Next.js generates HTML for each page in advance, instead of having it all done by client-side JavaScript. Pre-rendering can result in better performance and SEO. | |
| Each generated HTML is associated with minimal JavaScript code necessary for that page. When a page is loaded by the browser, its JavaScript code runs and makes the page fully interactive (this process is called [hydration](https://react.dev/reference/react-dom/client/hydrateRoot) in React). | |
| ### Pre-rendering | |
| Next.js has two forms of pre-rendering: **Static Generation** and **Server-side Rendering**. The difference is in **when** it generates the HTML for a page. | |
| - Static Generation: The HTML is generated at **build time** and will be reused on each request. | |
| - Server-side Rendering: The HTML is generated on **each request**. | |
| Importantly, Next.js lets you choose which pre-rendering form you'd like to use for each page. You can create a "hybrid" Next.js app by using Static Generation for most pages and using Server-side Rendering for others. | |
| We recommend using Static Generation over Server-side Rendering for performance reasons. Statically generated pages can be cached by CDN with no extra configuration to boost performance. However, in some cases, Server-side Rendering might be the only option. | |
| You can also use client-side data fetching along with Static Generation or Server-side Rendering. That means some parts of a page can be rendered entirely by clientside JavaScript. To learn more, take a look at the [Data Fetching](/docs/pages/building-your-application/data-fetching/client-side) documentation. | |