APIs help online retailers to gain more insight into their customers so they can offer them products tailored to their needs at exactly the right time. This is partly possible thanks to the knowledge an API can give you. APIs are becoming the key to the success of an e-commerce business because they build more scalable platforms.
There are many tools today available for testing mobile apps. Some of them are specific for iOS or Android environments and others suitable for any kind of operating system, both for testing with real users and for automatic tests.