---
title: "How to create a simple Custom Server in Next.js"
url: "https://www.bekk.christmas/post/2022/13/how-to-create-a-simple-custom-server-in-next-js"
authors: ["Toralf Frich"]
published: "2022-12-13"
updated: "2024-11-07T13:05:28Z"
language: "en-US"
type: "article"
tags: ["JavaScript", "React"]
keywords: ["nextjs", "custom server"]
---

# How to create a simple Custom Server in Next.js

Do you need help with setting up a simple custom server in Next.js? This trick will get you a long way!

## In short

Next.js usually creates its own server, but a custom server can be useful if you need to run code before the app starts or want custom server patterns. One simple approach is to mimic the standalone build’s generated server and load the needed config from required-server-files.json with fs and JSON.parse, giving you a basic server you can edit freely.

- **For:** Next.js developers who need a simple custom server
- **Good to know beforehand:** Basic Next.js knowledge

_AI-generated_

For many frameworks it is necessary to create your own server that listens and handles user interactions with your application.

In Next.js, a server is automatically generated 🤯. And, so, for most, there is no need to think about creating your own server. However, sometimes, it might be necessary with a custom server. In particular, due to two main reasons:

1. Wanting to run some code before the Next.js application is running ([a common issue](https://github.com/vercel/next.js/discussions/15341))
2. Creating custom server patterns

The reason why I wanted to create a custom server was due to reason 1. After multiple attempts, I figured that one way to do it was to replicate the server that Next.js generated when building a _standalone_ application. This is a bit “hacky”, but it is a lot easier than many of the other alternatives! In addition, it serves as a baseline for more complicated custom servers 📈

A standalone is just a smaller version of the application you are creating which only contains the necessary parts for running the application. You can create a standalone by adding _output: ‘standalone’_ to your config:

```tsx
/** @type {import('next').NextConfig} */
const nextConfig = {
    output: 'standalone',
};

module.exports = nextConfig;
```

After having built the application (with _yarn build_ or etc.), a standalone directory will be available in the root of your project. Inside it you will find ‘server.js’ which looks something like this:

```tsx
process.env.NODE_ENV = 'production'
process.chdir(__dirname)
const NextServer = require('next/dist/server/next-server').default
const http = require('http')
const path = require('path')

// Make sure commands gracefully respect termination signals (e.g. from Docker)
// Allow the graceful termination to be manually configurable
if (!process.env.NEXT_MANUAL_SIG_HANDLE) {
  process.on('SIGTERM', () => process.exit(0))
  process.on('SIGINT', () => process.exit(0))
}

let handler

const server = http.createServer(async (req, res) => {
  try {
    await handler(req, res)
  } catch (err) {
    console.error(err);
    res.statusCode = 500
    res.end('internal server error')
  }
})
const currentPort = parseInt(process.env.PORT, 10) || 3000

server.listen(currentPort, (err) => {
  if (err) {
    console.error("Failed to start server", err)
    process.exit(1)
  }
  const nextServer = new NextServer({
    hostname: 'localhost',
    port: currentPort,
    dir: path.join(__dirname),
    dev: false,
    customServer: false,
    conf: {"super-duper-long config automatically generated by Next.js"},
  })
  handler = nextServer.getRequestHandler()

  console.log("Listening on port", currentPort)
})
```

An easy way to create a custom server would be to copy the file above. However, we can't do this as there is a super-duper-long config that we need to get from ‘required-server-files.json' 🤔. My trick for getting this was by using _fs_ and _JSON.parse._ Hence, I ended up with a server file that looked like this:

```tsx
process.env.NODE_ENV = 'production';
process.chdir(__dirname);

const NextServer = require('next/dist/server/next-server').default;
const http = require('http');
const path = require('path');

const fs = require('fs');
const { config } = JSON.parse(fs.readFileSync('required-server-files.json'));

// Make sure commands gracefully respect termination signals (e.g. from Docker)
process.on('SIGTERM', () => process.exit(0));
process.on('SIGINT', () => process.exit(0));

let handler;

const server = http.createServer(async (req, res) => {
    try {
        await handler(req, res);
    } catch (err) {
        console.error(err);
        res.statusCode = 500;
        res.end('internal server error');
    }
});
const currentPort = parseInt(process.env.PORT, 10) || 3000;
 
server.listen(currentPort, (err) => {
    if (err) {
        console.error('Failed to start server', err);
        process.exit(1);
    }
    const addr = server.address();
    const nextServer = new NextServer({
        hostname: 'localhost',
        port: currentPort,
        dir: path.join(__dirname),
        dev: false,
        conf: config,
    });
    
    handler = nextServer.getRequestHandler();
});
```

It is important that the import path of ‘required-server-files.json’ is correct.

Tada! You now have a basic custom server that you can use and that you are free to edit it is as much as you like 👑.

Run your application with your new custom server by using the command below instead of _next start_:

```
yarn/npm build
node server.js
```

That was all for now! Bye 👋

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