Confused about choosing APIs & SDKs

[Bar92]

Hi guys,

I'm an iOS Developer and we're building an iOS app for a client.

The app should be more like a self-checkout app that will be public over an iPad.

There are key features we need and I got lost a little with Shopify's APIs / SDKs...

Here are the basic features we need:

1. User Management 
   Is it possible to manage end-users over Shopify?
   Is there a mailing list capabilities?
2. Inventory Management
3. Shopping Cart
4. Coupons / Campaigns

I would appreciate if you guys could help me just by pointing which API/SDK is good for which feature (if available by Shopify).

[vix]

Hey @Bar92 

All of our SDK's for custom storefronts are built upon the Storefront API. This includes our Mobile Buy SDKs that help you get up and running faster. Otherwise, you have the Admin APIs which are geared towards more internal admin events/managing data and the Checkout API for sales channels. 

Are you looking to process payment through this app? If so, you will want to look into becoming a sales channel: https://help.shopify.com/en/api/guides/sales-channel-sdk

In general, yes through the APIs you can handle user logins, inventory, and coupons. For a more Shopping Cart experience however, you will want to check out the Mobile Buy SDKs