Often times when developing a custom store for a client you will need to have access to the Shopify API. The Shopify API gives you access to lots of Shopify functionality, and more importantly it lets you trigger it using your custom object. I've used Private Apps to set up newsletter subscriptions, custom account settings, and custom reporting, just to name a few...

To Start, you'll need to set up a Private app for your storefront. Once you've created the app, you're going to use the credentials to authenticate your API calls.

Now that you have access tokens, you'll want to start setting up your server which will make the API calls and hook into your custom logic. In this example I'll be using a simple Express server to make API calls. I chose Express because it's simple to get running and cheap to host.

Create a new express application by following the instructions. Once you have a basic app set up. You'll want to install the Shopify Node API module. This is a helpful module which makes calling the API from your express server much easier.

Follow the instructions there and you're on your way to calling the API like a pro! Happy coding!