Application programming interfaces, or APIs, simplify software development and innovation by enabling applications to exchange data and functionality easily and securely.
An application programming interface, or API, enables companies to open up their applications’ data and functionality to external third-party developers, business partners, and internal departments within their companies. This allows services and products to communicate with each other and leverage each other’s data and functionality through a documented interface. Developers don't need to know how an API is implemented; they simply use the interface to communicate with other products and services. API use has surged over the past decade, to the degree that many of the most popular web applications today would not be possible without APIs.
An API is a set of defined rules that explain how computers or applications communicate with one another. APIs sit between an application and the web server, acting as an intermediary layer that processes data transfer between systems.
Here’s how an API works:
While the data transfer will differ depending on the web service being used, this process of requests and response all happens through an API. Whereas a user interface is designed for use by humans, APIs are designed for use by a computer or application.
APIs offer security by design because their position as middleman facilitates the abstraction of functionality between two systems—the API endpoint decouples the consuming application from the infrastructure providing the service. API calls usually include authorization credentials to reduce the risk of attacks on the server, and an API gateway can limit access to minimize security threats. Also, during the exchange, HTTP headers, cookies, or query string parameters provide additional security layers to the data.
For example, consider an API offered by a payment processing service. Customers can enter their card details on the frontend of an application for an ecommerce store. The payment processor doesn’t require access to the user’s bank account; the API creates a unique token for this transaction and includes it in the API call to the server. This ensures a higher level of security against potential hacking threats.
Whether you’re managing existing tools or designing new ones, you can use an application programming interface to simplify the process. Some of the main benefits of APIs include the following:
Because APIs allow companies to open up access to their resources while maintaining security and control, they have become a valuable aspect of modern business. Here are some popular examples of application programming interfaces you may encounter:
Nowadays, most application programming interfaces are web APIs that expose an application's data and functionality over the internet. Here are the four main types of web API:
As the use of web APIs has increased, certain protocols have been developed to provide users with a set of defined rules that specifies the accepted data types and commands. In effect, these API protocols facilitate standardized information exchange: