Application Programming Interfaces, or APIs are designed as the bridges between two programs. APIs allow for software systems and applications to interact with each other, share information, allow for users to input information in one application for use in another. They control the types of requests applications make between each other, how those requests are made, and what format those requests will take.
Sadly, they also share many of the same vulnerabilities as web apps.
APIs have facilitated the shift from single, monolithic web applications to microservices where loosely coupled services all interact together to form a cohesive product. This means that APIs play a major role in digital transformation, enabling user-oriented services in B2B applications — most notably including automation and integration. They also offer modern applications of all types the ability to incorporate rich user interfaces within single-page applications moving away from HTML-based backends.
They are a major component in every cloud-native application being used today and they make modern web applications flexible enough to work with the desires of modern web users. Essentially, if you’re using a web application today, it’s probably using one, if not many, APIs.