The Coffee Shop Kiosk

When I joined the Developers team at Square, the first thing I did was build an application that uses our APIs. Every new engineer on the team does this (you can read about my colleague’s example Android app here) so that we can walk in our customers’ shoes. It’s become a great tool to reinforce feedback from developers when building real world applications. For my project, I chose to build a customer-facing kiosk application as we’re seeing more and more demand for this type of custom application. For the application I built I used our Point of Sale API, which leverages the iOS app-switching API to enable apps to accept in-person payments using the Square Point of Sale app. We’ve also provided a Point of Sale SDK, which is a thin wrapper around our API that makes it incredibly fast and easy to get up and running.

The Coffee Shop is a customer-facing kiosk app that allows customers to order and pay for their drinks at a fictional coffee shop.

The Coffee Shop

The advantage of a kiosk is that customers can place their own orders, leaving baristas free to focus on making drinks and engaging with their customers instead of running the register. Because this is a customer-facing app, the interface needs to be both simple and fast. Customers should be able to easily choose a drink, customize it, and pay.

Data Model

The Drink model defines some basic properties like name and description, as well as an array of DrinkOptionGroups.

When you buy a drink at a coffee shop you usually have a few choices to make:

  • What size drink do you want?
  • Do you want whipped cream?
  • What type of milk do you want?

DrinkOptionGroup is a simple struct that can be used to model each of these use cases:

It defines a group of related options which can be applied to a drink. As an example, here’s a DrinkOptionGroup which defines the sizes that are available for a drink:

I’ve added a few different sizes at various price points (in cents) and specified that the customer must choose one and only one option. You can also define a DrinkOptionGroup where multiple options can be selected:

To bring it all together, here’s the drink definition for coffee:

In this sample app several drinks are defined statically in a configuration file, but you could also imagine them being pulled from a server.

App Flow

The app has two screens which are managed by the AppFlowController class. AppFlowController is a UIViewController subclass which is responsible for displaying and transitioning between screens in the app. It’s instantiated with an array of Drinks and displays them by showing the SelectDrinkViewController:

SelectDrinkViewController

Once the customer selects a drink, the CustomizeDrinkViewController is presented with the various options that can be used to customize it:

Customizing a drink

Finally, when the customer taps the checkout button, AppFlowController kicks off a Point of Sale API request which transitions the customer into the Square Point of Sale app so they can pay for their drink. Once the customer completes their payment, the Square Point of Sale app automatically switches back to The Coffee Shop to take the next customer’s order.

Checkout
Pro tip: Enable “Reduce Motion” in iOS Settings in order to improve the app-switching experience

Production apps are often much more complex than this simple example. By using Square’s APIs you don’t need to understand or worry about the complexity of accepting payments. Instead, you can focus on building a great experience for your customers.

All of the code for this app is available on Github and documentation is available on our developer portal. Feel free to clone the repo and try building a kiosk like The Coffee Shop for yourself!

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