One of the first questions historically asked when developing a web-based application is What desktop browsers and versions shall we support? These days, you should not be thinking so much about the software installed on the laptops and desktops of your users, but rather the devices they own.

The answer might still include a laptop or desktop, though no longer is it a safe assumption that these are the main devices your users use to interact with your application. Mobile phones, tablets, watches, or skills for voice recognition devices such as Alexa or, depending on your target market, they might be larger devices, such as cars or vending machines! So, make sure that you think big and understand all the types of devices your customers and their customers might use to interact with your application.

Developing against multiple devices can be expensive, not only to develop the solution, but also to perform testing across multiple devices. In this chapter, we will take a look at a range of options, ranging from those provided by Salesforce at no additional development cost, to building totally customized user interfaces using Lightning Components, Visualforce, and other technologies.