What is API (Application Programming Interface)?

An API is the interface used for building web applications. APIs provide building blocks for coders to use, and then the coders put those blocks together to create the program they are trying to build. Examples of APIs include Google Maps API (allows developers to embed Google maps on web pages), Twitter APIs (Twitter has two APIs—REST, which allows developers to access core Twitter data, and Search, which allows developers to interact with Twitter Search and trends data), and Amazon Product Advertising API (allows developers to access Amazon’s product database and advertise Amazon products on a website).