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Deploying

Congratulations, it's time to ship to production.

You can deploy managed Next.js with Vercel, or self-host on a Node.js server, Docker image, or even static HTML files. When deploying using next start, all Next.js features are supported.

Production Builds

Running next build generates an optimized version of your application for production. HTML, CSS, and JavaScript files are created based on your pages. JavaScript is compiled and browser bundles are minified using the Next.js Compiler to help achieve the best performance and support all modern browsers.

Next.js produces a standard deployment output used by managed and self-hosted Next.js. This ensures all features are supported across both methods of deployment. In the next major version, we will be transforming this output into our Build Output API specification.

Managed Next.js with Vercel

Vercel, the creators and maintainers of Next.js, provide managed infrastructure and a developer experience platform for your Next.js applications.

Deploying to Vercel is zero-configuration and provides additional enhancements for scalability, availability, and performance globally. However, all Next.js features are still supported when self-hosted.

Learn more about Next.js on Vercel or deploy a template for free to try it out.

Self-Hosting

You can self-host Next.js in three different ways:

Node.js Server

Next.js can be deployed to any hosting provider that supports Node.js. Ensure your package.json has the "build" and "start" scripts:

package.json
{
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "next start"
  }
}

Then, run npm run build to build your application. Finally, run npm run start to start the Node.js server. This server supports all Next.js features.

Docker Image

Next.js can be deployed to any hosting provider that supports Docker containers. You can use this approach when deploying to container orchestrators such as Kubernetes or when running inside a container in any cloud provider.

  1. Install Docker on your machine
  2. Clone our example (or the multi-environment example)
  3. Build your container: docker build -t nextjs-docker .
  4. Run your container: docker run -p 3000:3000 nextjs-docker

Next.js through Docker supports all Next.js features.

Static HTML Export

Next.js enables starting as a static site or Single-Page Application (SPA), then later optionally upgrading to use features that require a server.

Since Next.js supports this static export, it can be deployed and hosted on any web server that can serve HTML/CSS/JS static assets. This includes tools like AWS S3, Nginx, or Apache.

Running as a static export does not support Next.js features that require a server. Learn more.

Good to know:

Features

Image Optimization

Image Optimization through next/image works self-hosted with zero configuration when deploying using next start. If you would prefer to have a separate service to optimize images, you can configure an image loader.

Image Optimization can be used with a static export by defining a custom image loader in next.config.js. Note that images are optimized at runtime, not during the build.

Good to know:

  • When self-hosting, consider installing sharp for more performant Image Optimization in your production environment by running npm install sharp in your project directory. On Linux platforms, sharp may require additional configuration to prevent excessive memory usage.
  • Learn more about the caching behavior of optimized images and how to configure the TTL.
  • You can also disable Image Optimization and still retain other benefits of using next/image if you prefer. For example, if you are optimizing images yourself separately.

Middleware

Middleware works self-hosted with zero configuration when deploying using next start. Since it requires access to the incoming request, it is not supported when using a static export.

Middleware uses a runtime that is a subset of all available Node.js APIs to help ensure low latency, since it may run in front of every route or asset in your application. This runtime does not require running “at the edge” and works in a single-region server. Additional configuration and infrastructure are required to run Middleware in multiple regions.

If you are looking to add logic (or use an external package) that requires all Node.js APIs, you might be able to move this logic to a layout as a Server Component. For example, checking headers and redirecting. You can also use headers, cookies, or query parameters to redirect or rewrite through next.config.js. If that does not work, you can also use a custom server.

Environment Variables

Next.js can support both build time and runtime environment variables.

By default, environment variables are only available on the server. To expose an environment variable to the browser, it must be prefixed with NEXT_PUBLIC_. However, these public environment variables will be inlined into the JavaScript bundle during next build.

To read runtime environment variables, we recommend using getServerSideProps or incrementally adopting the App Router. With the App Router, we can safely read environment variables on the server during dynamic rendering. This allows you to use a singular Docker image that can be promoted through multiple environments with different values.

import { unstable_noStore as noStore } from 'next/cache';
 
export default function Component() {
  noStore();
  // cookies(), headers(), and other dynamic functions
  // will also opt into dynamic rendering, making
  // this env variable is evaluated at runtime
  const value = process.env.MY_VALUE
  ...
}

Good to know:

Caching and ISR

Next.js can cache responses, generated static pages, build outputs, and other static assets like images, fonts, and scripts.

Caching and revalidating pages (using Incremental Static Regeneration (ISR) or newer functions in the App Router) use the same shared cache. By default, this cache is stored to the filesystem (on disk) on your Next.js server. This works automatically when self-hosting using both the Pages and App Router.

You can configure the Next.js cache location if you want to persist cached pages and data to durable storage, or share the cache across multiple containers or instances of your Next.js application.

Automatic Caching

  • Next.js sets the Cache-Control header of public, max-age=31536000, immutable to truly immutable assets. It cannot be overridden. These immutable files contain a SHA-hash in the file name, so they can be safely cached indefinitely. For example, Static Image Imports. You can configure the TTL for images.
  • Incremental Static Regeneration (ISR) sets the Cache-Control header of s-maxage: <revalidate in getStaticProps>, stale-while-revalidate. This revalidation time is defined in your getStaticProps function in seconds. If you set revalidate: false, it will default to a one-year cache duration.
  • Dynamically rendered pages set a Cache-Control header of private, no-cache, no-store, max-age=0, must-revalidate to prevent user-specific data from being cached. This applies to both the App Router and Pages Router. This also includes Draft Mode.

Static Assets

If you want to host static assets on a different domain or CDN, you can use the assetPrefix configuration in next.config.js. Next.js will use this asset prefix when retrieving JavaScript or CSS files. Separating your assets to a different domain does come with the downside of extra time spent on DNS and TLS resolution.

Learn more about assetPrefix.

Configuring Caching

By default, generated cache assets will be stored in memory (defaults to 50mb) and on disk. If you are hosting Next.js using a container orchestration platform like Kubernetes, each pod will have a copy of the cache. To prevent stale data from being shown since the cache is not shared between pods by default, you can configure the Next.js cache to provide a cache handler and disable in-memory caching.

To configure the ISR/Data Cache location when self-hosting, you can configure a custom handler in your next.config.js file:

next.config.js
module.exports = {
  cacheHandler: require.resolve('./cache-handler.js'),
  cacheMaxMemorySize: 0, // disable default in-memory caching
}

Then, create cache-handler.js in the root of your project, for example:

cache-handler.js
const cache = new Map()
 
module.exports = class CacheHandler {
  constructor(options) {
    this.options = options
  }
 
  async get(key) {
    // This could be stored anywhere, like durable storage
    return cache.get(key)
  }
 
  async set(key, data, ctx) {
    // This could be stored anywhere, like durable storage
    cache.set(key, {
      value: data,
      lastModified: Date.now(),
      tags: ctx.tags,
    })
  }
 
  async revalidateTag(tag) {
    // Iterate over all entries in the cache
    for (let [key, value] of cache) {
      // If the value's tags include the specified tag, delete this entry
      if (value.tags.includes(tag)) {
        cache.delete(key)
      }
    }
  }
}

Using a custom cache handler will allow you to ensure consistency across all pods hosting your Next.js application. For instance, you can save the cached values anywhere, like Redis or AWS S3.

Good to know:

  • revalidatePath is a convenience layer on top of cache tags. Calling revalidatePath will call the revalidateTag function with a special default tag for the provided page.

Build Cache

Next.js generates an ID during next build to identify which version of your application is being served. The same build should be used and boot up multiple containers.

If you are rebuilding for each stage of your environment, you will need to generate a consistent build ID to use between containers. Use the generateBuildId command in next.config.js:

next.config.js
module.exports = {
  generateBuildId: async () => {
    // This could be anything, using the latest git hash
    return process.env.GIT_HASH
  },
}

Version Skew

Next.js will automatically mitigate most instances of version skew and automatically reload the application to retrieve new assets when detected. For example, if there is a mismatch in the build ID, transitions between pages will perform a hard navigation versus using a prefetched value.

When the application is reloaded, there may be a loss of application state if it's not designed to persist between page navigations. For example, using URL state or local storage would persist state after a page refresh. However, component state like useState would be lost in such navigations.

Vercel provides additional skew protection for Next.js applications to ensure assets and functions from the previous build are still available while the new build is being deployed.

Manual Graceful Shutdowns

When self-hosting, you might want to run code when the server shuts down on SIGTERM or SIGINT signals.

You can set the env variable NEXT_MANUAL_SIG_HANDLE to true and then register a handler for that signal inside your _document.js file. You will need to register the environment variable directly in the package.json script, and not in the .env file.

Good to know: Manual signal handling is not available in next dev.

package.json
{
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "start": "NEXT_MANUAL_SIG_HANDLE=true next start"
  }
}
pages/_document.js
if (process.env.NEXT_MANUAL_SIG_HANDLE) {
  process.on('SIGTERM', () => {
    console.log('Received SIGTERM: cleaning up')
    process.exit(0)
  })
  process.on('SIGINT', () => {
    console.log('Received SIGINT: cleaning up')
    process.exit(0)
  })
}