In modern IT architectures, the front end and back end are designed to function independently from one another, communicating through a set of agreed-upon interactions -- most often via RESTful APIs. I have written previously on the different approaches for building the back end and designing the APIs. The potential impact of your APIs however is higher: they can be used in several ways that can impact your business.
Back end for your own front end
The primary use of the data back end is to serve, via APIs, the front-end systems that will be at the core of the customer experience. Usually (and depending on your business) these can include mobile apps, websites/applications, connected objects on the Internet of things, and so on.
One of the keys to growth in this domain is to incorporate more data and interactions in the same channel: add dynamic promotions or couponing in the mobile app, add customer chat or support tools on the website. This can be performed much more easily if these additional processes are made available via APIs as well -- the app or site becomes a consumer of several APIs instead of just one.
Similarly, services or promotions from third-party vendors/partners can be added to a front-end tool, using the same API-driven logic.
Unified access for all interaction channels
Often, customer service agents have a very different view of the data and services than the customer himself. Think of the last time you were in a store and had to point the salesman to their website to check a special offer that did not appear in their computer -- sounds familiar?
In most cases it’s about dealing with legacy: These systems were designed before the new shiny mobile app or before the latest refactoring of the website. As the saying goes: if it isn’t broken, why fix it?
In almost all of these cases, it would actually serve the business a lot better to "fix" these legacy systems, so they can embrace and use the same APIs that the client-facing front ends also use. This way, both sides get the same view on the same data, and soon enough you can stop maintaining legacy systems that actually cost a lot more than you think.
Back end for your partners’ front end
The same way you can embed partner data and processes in your own app/site, the APIs you have designed and deployed to serve your front end can also be made available to partners, enabling them to do the opposite -- giving you access to untapped segments of your target.
Delivery channel for data monetization
For many companies, selling data remains a manual process that requires extraction, transformation, and the actual delivery of a file to the customer. This process is typically not scalable and does not enable the smooth on-boarding of new customers.
Why not leverage the same APIs you already use to exchange this data with front ends, with partners, to become your delivery mechanism?