How to host Nodejs API on Netlify for free

Hosting a Nodejs API is not very critical these days. In this era of cloud computing and serverless environment, you don't have to create your server and configure everything from scratch.

These days, most hosting providers give a free tier to new users. If you are a hobbyist and only want to host some small projects, then these free resources are enough. Render, and Railway are such types of solutions you can check out.

If you don't want a stateful server to manage steady connection eg, WebSockets with the client, then you can also opt for serverless offerings. All major cloud providers have their serverless offerings.

The main benefit of serverless computing is its cost-effectiveness. If you are building a startup and don't want to manage servers of your own, then you can opt for serverless. this saves you a lot of time and also money.

What is Netlify functions

Netlify function is a serverless offering from Netlify. Netlify function is a wrapper on AWS lambda functions and comes with a very generous free tier.

Netlify function is built as an extension to their JAMstack offering. Using Netlify functions, now a static JAMStack website can run server code and give a personalized response to a user.

The most important part is, you can include the server code in the same project. During the build, Netlify can extract the code and process it accordingly and provide an API endpoint for the developer.

You can use Javascript, Typescript, and Golang to code your Netlify functions.

Setting up a Netlify functions project

To set up your Netlify functions project create netlify/functions/ directory in your project root.

mkdir -p netlify/functions

If you don't have any front-end and only want to host a Nodejs API, then initiate a Nodejs project first using npm init and then create netlify/functions directory in your project root.

npm init -y
mkdir -p netlify/functions

Define API routes in Netlify functions

The base URL of an API hosted on the Netlify function is https://yourdomain.com/.netlify/functions/. Yes, I know it is very long and there is a way to change this using proxies. I am discussing this in the later part of this blog.

Netlify function uses file-based routing. You can use 3 different ways to define an API route in Netlify functions. For example, you want to host your API in https://yourdomain.com/.netlify/functions/hello endpoint. For this, your directory structure should be one of these 3 ways.

1. netlify/functions/hello.js
2. netlify/functions/hello/index.js
3. netlify/functions/hello/hello.js

Basic Nodejs API for Netlify functions

Continuing from the previous example, we want to host an API in https://yourdomain.com/.netlify/functions/hello endpoint and therefore created a hello.js file inside the netlify/functions directory.

Inside the hello.js file, we will write a simple function that returns a JSON hello world response when invoked.

exports.handler = async function (event, context) {
    return {
        statusCode: 200,
        headers: { "content-type": "application/json" },
        body: JSON.stringify({ msg: "Hello world" }),
    }
};

In the above code example, I have exported an async function which returns an object with a JSON body. In addition to this, I have sent the appropriate header and a 200 status code.

The event argument in the exported function can provide you with some basic yet useful set of information.

{
  "path": "Path parameter (original URL encoding)",
  "httpMethod": "Incoming request’s method name",
  "headers": {Incoming request headers},
  "queryStringParameters": {Query string parameters},
  "body": "A JSON string of the request payload",
  "isBase64Encoded": "A boolean flag to indicate if the applicable request payload is Base64-encoded"
}

Local Netlify functions development

After you finish developing your Netlify function, install netlify-cli npm package in your project.

npm i -D netlify-cli

Then add an npm script in the package.json file to run the local development server.

{
    "name": "netlify-function-hello",
    "version": "1.0.0",
    "description": "",
    "scripts": {
        "serve": "netlify functions:serve"
    },
    "devDependencies": {
        "netlify-cli": "^13.2.2"
    }
}

Now execute npm run serve to run your local dev server. Visit http://localhost:9999/.netlify/functions/hello to invoke your first Netlify function.

Change the function directory and port

You can customize the Netlify function directory and port using a netlify.toml file in your project root.

If you want to change your functions directory from netlify/ to netlify-functions/ and change the port from 9999 to 5000, then the netlify.toml file should look like this.

[dev]
functions = "netlify-functions"
functionsPort = 5000

Deploying Netlify functions from Github

To deploy your Netlify function, first, initiate a git repository and commit all the changes. Don't forget to create a .gitignore file and ignore the node-modules directory.

git init
touch .gitignore
git add .
git commit -m"first commit"

The content inside .gitignore file should look like this.

node_modules
.netlify
.gitignore

Now create a new GitHub repository and push all the changes to that repository.

git branch -M main
git remote add origin "github repository link"
git push -u origin main

Now import this repository in a new Netlify project and the rest will be done by Netlify automatically for you.

Once you finish deploying your function, Netlify gives you an URL with which you can access your Nodejs API by visiting https://<baseurl.com>/.netlify/functions/hello endpoint.

Proxy URL in Netlify functions

The deployed endpoint is too long and boring. But the good news is you can change it using a proxy. Let's see how to do that.

Inside your netlify.toml file, add a redirect block. There you can define redirect from and redirect to parameters for incoming requests.

[[redirects]]
from = "/api/*"
to = "/.netlify/functions/:splat"
status = 200

Now, every request comes to the /api/ endpoint, and Netlify redirects it to /.netlify/functions/ endpoint. It means, now you can access your deployed API in https://<baseurl.com>/api/hello endpoint.

Conclusion

Netlify function is a great way to deploy a Nodejs API in a serverless environment. Unlike AWS lambda functions, Netlify function is very developer friendly and easy to use. In addition to this, a free uses quota also attracts developers to host their hobby Nodejs APIs in the Netlify functions.

In this blog, we have discussed an end-to-end strategy to code and deploy a Nodejs API in the Netlify function. We have also seen how to test the function locally. In the end, You have learned how to use a proxy to redirect incoming requests in Netlify functions.

If you want to explore the serverless computing options, you much look into Cloudflare Worker and Deno deploy. These two are not based on Nodejs but you can run javascript and typescript functions in them. They provide minimum latency and maximum performance.

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