What is an API?

An Application Programming Interface (API) serves as a bridge between different software applications, facilitating data exchange. It’s essentially a set of protocols and tools that define how different software components should interact.

It’s crucial to distinguish APIs from user interfaces. While user interfaces interact directly with people, accepting inputs and displaying outputs, APIs work behind the scenes. They process data received from one software module and transmit the results to another, without any direct user interaction.

The API Mechanism

APIs typically function through a request-response model between a client and a server. The client-side usually consists of front-end applications that users interact with directly. On the other hand, the server manages backend operations and database interactions. In this setup, the API acts as an intermediary, enabling the smooth flow of data requests and responses between these two elements.

API Classifications

APIs can be categorised in various ways, including their accessibility and their intended purpose.

API Accessibility Levels

When it comes to accessibility, APIs generally fall into three categories:

1. Private APIs: These are for internal use within an organisation.
2. Partner APIs: These are shared with specific business partners.
3. Public APIs: These are openly available for use by external developers.

Each type of API serves different purposes and has varying levels of security and access control.