Fast abstract ↬

On this tutorial, Paul Scanlon explains how one can construct an API by utilizing Gatsby Capabilities and what you want to remember when deploying it to Gatsby Cloud.

You’ve most likely heard about Serverless Capabilities, however in the event you haven’t, Serverless Capabilities present performance usually related to server-side applied sciences that may be applied alongside front-end code with out getting caught up in server-side infrastructures.

With server-side and client-side code coexisting in the identical code base, front-end builders like myself can lengthen the attain of what’s doable utilizing the instruments they already know and love.


Coexistence is nice however there are not less than two situations I’ve encountered the place utilizing Serverless Capabilities on this manner weren’t fairly the best match for the duty at hand. They’re as follows:

  1. The entrance finish couldn’t assist Serverless Capabilities.
  2. The identical performance was required by multiple entrance finish.

To assist present some context right here’s one instance of each factors 1 and a pair of named above. I keep an Open-source mission known as MDX Embed, you’ll see from the docs website that it’s not a Gatsby web site. It’s been constructed utilizing Storybook and Storybook by itself supplies no Serverless Perform capabilities. I needed to implement “Pay what you need” contributions to assist fund this mission and I needed to make use of Stripe to allow safe funds however with no safe “backend” This is able to not have been doable.

By abstracting this performance away into an API constructed with Gatsby Capabilities I used to be capable of obtain what I needed with MDX Embed and in addition re-use the identical performance and allow “Pay what you need” performance for my weblog.

You possibly can learn extra about how I did that right here: Monetize Open-Supply Software program With Gatsby Capabilities And Stripe.

It’s at this level that utilizing Gatsby Capabilities can act as a type of Again finish for entrance finish or BFF 😊 and growing on this manner is extra akin to growing an API (Software Programming Interface).

APIs are utilized by front-end code to deal with issues like, logins, real-time information fetching, or safe duties that aren’t suitably dealt with by the browser alone. On this tutorial, I’ll clarify how one can construct an API utilizing Gatsby Capabilities and deploy it to Gatsby Cloud.

Extra after soar! Proceed studying under ↓

Preflight Checks

Gatsby Capabilities work when deployed to Gatsby Cloud or Netlify, and on this tutorial, I’ll be explaining how one can deploy to Gatsby Cloud so that you’ll want to enroll and create a free account first.

You’re additionally going to want both a GitHub, GitLab or BitBucket account, that is how Gatsby Cloud reads your code after which builds your “website”, or on this case, API.

For the needs of this tutorial, I’ll be utilizing GitHub. If you happen to’d desire to leap forward, the completed demo API code might be discovered on my GitHub.

Getting Began

Create a brand new dir someplace in your native drive and run the next in your terminal. It will arrange a default bundle.json.

npm init -y


Kind the next into your terminal to put in the required dependencies.

npm set up gatsby react react-dom


It’s probably your API received’t have any “pages” however to keep away from seeing Gatsby’s default lacking web page warning once you go to the basis URL within the browser, add the next to each src/pages/index.js and src/pages/404.js.

//src/pages/index.js & src/pages/404.js

export default () => null;


Add the next to src/api/my-first-function.js.

I’ll clarify a bit of later what 'Entry-Management-Enable-Origin', '*' means, however in brief, it makes positive that your APIs from different origins aren’t blocked by CORS.


export default operate handler(req, res) {
  res.setHeader('Entry-Management-Enable-Origin', '*');

  res.standing(200).json({ message: 'A okay!' });


Add the next to bundle.json.


  "scripts": {
    "develop": "gatsby develop",
    "construct": "gatsby construct"

Begin The Gatsby Improvement Server

To spin up the Gatsby improvement server run the next in your terminal.

npm run develop

Make A Request From The Browser

With the Gatsby’s improvement server working you’ll be able to go to http://localhost:8000/api/my-first-function, and since this can be a easy GET request it’s best to see the next in your browser.

  "message": "A okay!"

Congratulations 🎉

You’ve simply developed an API utilizing Gatsby Capabilities.


In case you are seeing the above response in your browser it’s protected to imagine your operate is working accurately domestically, within the following steps I’ll clarify how one can deploy your API to Gatsby Cloud and entry it utilizing an HTTP request from CodeSandbox.

Push Code To Git

Earlier than trying to deploy to Gatsby Cloud you’ll must have pushed your code to your Git supplier of alternative.

Gatsby Cloud

Log into your Gatsby Cloud account and search for the large purple button that claims “Add website +”.

Screenshot of Gatsby Cloud Add site

Add a website to Gatsby Cloud. (Massive preview)

Within the subsequent step, you’ll be requested to both Import from a Git repository or Begin from a Template, choose Import from Git Repository and hit subsequent.

Screenshot select import from a Git repository

Choose import from a Git repository. (Massive preview)

As talked about above Gatsby Cloud can hook up with both GitHub, GitLab or Bitbucket. Choose your most well-liked Git supplier and hit subsequent.

Screenshot of Gatsby Cloud Git provider selection

Choose out of your most well-liked Git supplier. (Massive preview)

Together with your Git supplier linked, you’ll be able to seek for your repository, and provides your website a reputation.

Screenshot of Gatsby Cloud search for site from Git provider

Seek for your website out of your Git supplier. (Massive preview)

When you’ve chosen your repository and named your website hit subsequent.

You possibly can skip the “Integrations” and “Setup” as we received’t be needing these.

If all has gone to plan your must be seeing one thing much like the under screenshot.

Screenshot of successfully deployed site

‘website’ efficiently constructed and deployed on Gatsby Cloud. (Massive preview)

You’ll see close to the highest on the left-hand facet of the display screen a URL that ends with, this would be the URL in your API and any capabilities you create might be accessed by including /api/name-of-function to the tip of this URL.

E.g, the entire deployed model of my-first-function.js for my demo API is as follows:

Demo API: My First Perform.

Testing Your API

Visiting the URL of your API is one factor but it surely’s not likely how APIs are usually used. Ideally to check your API it’s essential make a request to the operate from a totally unrelated origin.

It’s right here the place res.setHeader('Entry-Management-Enable-Origin', '*'); involves the rescue. While it’s not all the time fascinating to permit any area (web site) to entry your capabilities, for essentially the most half, public capabilities are simply that, public. Setting the Entry Management header to a worth of * means any area can entry your operate, with out this, any area apart from the area the API is hosted on might be blocked by CORS.

Right here’s a CodeSandbox that makes use of my-first-function from my demo API. You possibly can fork this and alter the Axios request URL to check your operate.

CodeSandbox: My First Perform

CodeSandbox: My First Function

(Massive preview)

Getting Fancier

Sending a response out of your API that claims message: "A okay!" isn’t precisely thrilling so within the subsequent bit I’ll present you how one can question the GitHub REST API and make a private profile card to show by yourself website utilizing the API you simply created, and it’ll look a bit of like this.

CodeSandbox: Demo profile card

CodeSandbox: Demo profile card

(Massive preview)


To make use of the GitHub REST API you’ll want to put in @octokit/relaxation bundle.

npm set up @octokit/relaxation

Get GitHub Person Uncooked

Add the next to src/api/get-github-user-raw.js.

// src/api/get-github-user-raw.js

import { Octokit } from '@octokit/relaxation';

const octokit = new Octokit({

export default async operate handler(req, res) {
  res.setHeader('Entry-Management-Enable-Origin', '*');

  strive {
    const { information } = await octokit.request(`GET /customers/{username}`, {
      username: 'PaulieScanlon'

    res.standing(200).json({ message: 'A okay!', person: information });
  } catch (error) {
    res.standing(500).json({ message: 'Error!' });

Entry Token

To speak with the GitHub REST API you’ll want an entry token. You may get this by following the steps on this information from GitHub: Creating A Private Entry Token.

.env Variables

To maintain your entry token safe add the next to .env.improvement and .env.manufacturing.


You possibly can learn extra about Gatsby setting variables on this information from Gatsby: Surroundings Variables.

Begin Improvement Server

As you probably did earlier than begin the Gatsby improvement server by typing the next in your terminal.

npm run develop

Make A Request From The Browser

With the Gatsby improvement server working you’ll be able to go to http://localhost:8000/api/get-github-user-raw, and since this too is a straightforward GET request it’s best to see the next in your browser. (I’ve eliminated a part of the response for brevity.)

  "message": "A okay!",
  "person": {
    "login": "PaulieScanlon",
    "id": 1465706,
    "node_id": "MDQ6VXNlcjE0NjU3MDY=",
    "avatar_url": "",
    "gravatar_id": "",
    "url": "",
    "kind": "Person",
    "site_admin": false,
    "identify": "Paul Scanlon",
    "firm": "Paulie Scanlon Ltd.",
    "weblog": "",
    "location": "Worthing",
    "e mail": "[email protected]",
    "hireable": true,
    "bio": "Jamstack Developer / Technical Content material Author (freelance)",
    "twitter_username": "pauliescanlon",
    "created_at": "2012-02-23T13:43:26Z",
    "two_factor_authentication": true,

Right here’s a CodeSandbox instance of the total uncooked response.

CodeSandbox: Uncooked Response

CodeSandbox: Raw Response

(Massive preview)

You’ll see from the above that there’s numerous information returned that I don’t actually need, this subsequent bit is totally as much as you because it’s your API however I’ve discovered it useful to govern the GitHub API response a bit of bit earlier than sending it again to my frontend code.

If you happen to’d love to do the identical you can create a brand new operate and add the next to src/api/get-github-user.js.

// src/api/get-github-user.js

import { Octokit } from '@octokit/relaxation';

const octokit = new Octokit({

export default async operate handler(req, res) {
  res.setHeader('Entry-Management-Enable-Origin', '*');

  strive {
    const { information } = await octokit.request(`GET /customers/{username}`, {
      username: 'PaulieScanlon'

      message: 'A okay!',
      person: {
        identify: information.identify,
        blog_url: information.weblog,
        picture: information.avatar_url,
        githubUsername: `@${information.login}`,
        githubUrl: information.html_url,
        twitterUsername: `@${information.twitter_username}`,
        twitterUrl: `${information.twitter_username}`
  } catch (error) {
    res.standing(500).json({ message: 'Error!' });

You’ll see from the above that moderately than returning the entire information object returned by the GitHub REST API I pick simply the bits I want, rename them and add a number of bits earlier than the username and URL values. This makes life a bit simpler once you come to render the info within the frontend code.

Right here’s a CodeSandbox instance of the formatted response.

CodeSandbox: Formatted Response

CodeSandbox: Formatted Response

(Massive preview)

That is similar to the Profile Card CodeSandbox from earlier, however I’ve additionally printed the info out so you’ll be able to see how every manipulated information merchandise is used.

It’s price noting at this level that each one 4 of the CodeSandbox demos on this tutorial are utilizing the demo API, and none of them are constructed utilizing Gatsby or hosted on Gatsby Cloud — cool ay!

.env Variables In Gatsby Cloud

Earlier than you deploy your two new capabilities you’ll want so as to add the GitHub Entry token to the setting variables part in Gatsby Cloud.

Screenshot of Gatsby Cloud with Site Settings

(Massive preview)

The place To Go From Right here?

I requested myself this very query. Usually talking serverless capabilities are utilized in client-side requests and while that’s advantageous I puzzled in the event that they may be used at construct time to statically “bake” information right into a web page moderately than counting on JavaScript which can or might not be disabled within the person’s browser.

…in order that’s precisely what I did.

Right here’s a type of information dashboard that makes use of information returned by Gatsby Capabilities at each run and construct time. I constructed this website utilizing Astro and deployed it GitHub Pages.

The rationale I believe this can be a nice strategy is as a result of I’m capable of re-use the identical performance on each the server and within the browser with out duplicating something.

On this Astro construct I hit the identical endpoint uncovered by my API to return information that’s then both baked into the web page (nice for web optimization) or fetched at run time by the browser (nice for displaying recent or as much as the minute dwell information).

Information Dashboard

The info displayed on the left of the positioning is requested at construct time and baked into the web page with Astro. The info on the best of the web page is requested at runtime utilizing a client-side request. I’ve used barely totally different endpoints uncovered by the GitHub REST API to question totally different GitHub person accounts which create the totally different lists.

Data Dashboard

(Massive preview)

All the pieces you see on this website is offered by my extra full API. I’ve known as it: Paulie API and I take advantage of it for numerous my web sites.

Paulie API

Paulie API just like the API from this tutorial is constructed with Gatsby however as a result of Gatsby can act as each a website and an API I’ve used it to doc how all my capabilities work and every endpoint has its personal web page that can be utilized as an interactive playground… be at liberty to take a look round.

Paulie API

(Massive preview)

So, there you’ve it, A Gatsby Capabilities API that can be utilized by any client-side or server-side code, from any web site constructed with any tech stack. 🤯

Give it a go and I’d be very to see what you construct. Be happy to share within the feedback under or come discover me on Twitter: @PaulieScanlon.

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