API (application programming interface)

What is an API?
How does an API work?
Where is the API used?
Advantages of using an API
How to connect to an API?

What is an API?

An API, or Application Programming Interface, is a set of rules and standards that allows different programs to interact with each other. It is an important technology that enables developers to quickly integrate features and capabilities already implemented in other applications into their own solutions. For example, with the help of an API, one can request data about the current exchange rate or use a text translation feature.

An example of API usage could be a weather forecasting application that requests current meteorological data from the relevant service via an API. This simplifies the development process, allowing developers to focus on creating unique features by integrating existing solutions.

Although programs can interact with each other without using an API, such methods are generally complex and inefficient. An API provides a standardized and simplified way to exchange data, making it a fundamental tool in modern programming.

How does an API work?

The operation of an API is based on the principle of exchanging requests and responses between a client and a server. The client program formulates a request to the API asking it to perform a specific operation. This request is sent to the API, which then forwards it to the provider program that executes the required function. After the operation is completed, the API returns the result back to the client.

At the programming level, an API serves as a contract, describing how exactly the interaction between applications occurs. It includes:

Methods that the API can perform;
Input data for each method;
Output data returned by the API.

Modern web APIs typically exchange data in JSON format, making them easy to read for both humans and machines. For example, a pizza order request might return a response containing the readiness status, expected wait time, and type of order.

Where is the API used?

APIs are used in various fields and for many tasks. Here are some of the main areas of its application:

Mapping services: Integration of maps from services like Google or Yandex allows for displaying branches, adding images, and comments.
Aggregators: Websites that collect information from different sources most often use APIs to obtain data.
Payment services: When using bank cards, terminals call the bank's API to process transactions.
Social media authentication: Users can quickly register on sites using their social media accounts.
Program integrations: Two or more services can synchronize and exchange data, significantly simplifying workflows.

Advantages of using an API

Using APIs provides many benefits to both developers and businesses:

Accelerated development: Ready-made solutions save time and resources, avoiding the need to develop everything from scratch.
Protection of development: APIs can hide certain functions of the program, making them available only through the interface.
Standardization of interaction: Simplifies integration between different services.
Cost reduction: Using existing solutions reduces the budget for development.
Additional income: Developers can offer paid access to their APIs to other programmers.
Process automation: APIs allow for automating data exchange between systems, eliminating manual input.

How to connect to an API?

Each application or service has its own documentation for working with APIs. Here are the main steps necessary for API integration:

Developing a program: Creating an application, for example, for sending email messages.
Creating API documentation: Describing how other developers can use your application.
Gaining access to the API: Setting up an account and obtaining an API key for private APIs.
Installing the API client: Integrating the API code into your application.
Testing: Checking the operation of the API and its responses to requests.