APIs have been around since 1960, without API the digital experiences that we expect every day as a consumer wouldn’t be possible. APIs are doing everything from driving information which marketing campaigns to connecting mobile apps, to streamlining internal operations. API acts as a messenger and runs back and forth between your application database and devices. API is a software intermediary that allows two applications to talk to each other without any glitches. Every time we use an app like Facebook to send an instant message or to chat with a friend whenever you check the weather on your phone you are using an API. APIs provide effortless integration, it allows the customer to access data server or any other application in a very stable and secure way. Mobile phones and devices embedded with sensors fit perfectly with the service base structure of API. Cloud Computing is already rising and API is needed in the initial migration and integration with the other system in the cloud. API is what that gives values to your application, is what makes our phone smart and is what streamline the business processes. So if an API doesn’t work effectively and efficiently it will not be adopted by the software giants also if an API breaks because of errors that aren’t detected there is a threat of not only breaking a single application but an entire chain of business processes associated with it. So the solution is to test the API before it is put to use.
Have a look into the most frequently asked interview question on API Testing.