Google, Facebook, Twitter, and Amazon all have their own APIs which allow for integration with personal and business applications. By allowing their information to be accessed by other applications, they open up a range of prospects for expansions of their platforms. API development may allow for the expansion of an application into a full-fledged platform that could possibly become an integral part of a larger market.
According to Layer 7, 85% of large companies will have API programs in 5 years. Since it is an emerging market, it would be valuable to contribute to the growing demand by businesses, consumers, and developers.
APIs reduce development time by using functionality that has already been established by other companies. APIs are accessible both privately and publicly. Private APIs can connect businesses to other businesses or their customers and restrict access from others, while a public API allows access to anybody that would like to use it. Either way, API integration saves time and effort by working with methods that have already been tested and approved.