What is an API (Application Programming Interface) and why is it needed?

An API (Application Programming Interface) is a set of rules that allows different programs to "talk" to each other. When one application requests data or an action from another, the API receives the request, processes it, and returns the result — usually in JSON or XML format.

Simply put: an API is an intermediary that helps applications exchange information.

What is an API in simple terms?

Imagine you have a weather forecast application. It doesn't store all climate data, but rather accesses a third-party service via an API.
The API transmits the request ("what's the weather in Moscow tomorrow?") and returns a ready-made answer, which the application then shows you.

Hundreds of services we use every day work this way.

Why are APIs so important for business and technology?

• Saving time and money. Developers use ready-made solutions instead of writing everything from scratch.
• Flexibility and scalability. New features can be added without redoing the entire system.
• Process automation. APIs connect different programs directly — without manual data entry.
• Cloud integration. Modern companies build services on cloud platforms, and all of this relies on APIs.

In essence, it's impossible to imagine modern web services, mobile applications, and corporate systems without APIs.

Examples of API usage in everyday life

We often don't think about it, but almost every convenience in the digital world works through an API:

• Social networks. The "Share" button or logging in via Google — that's an API call.
• Online payments. Stores connect PayPal, Stripe, or Yandex.Kassa APIs to accept payments.
• Maps and navigation. Taxis and food delivery services use mapping service APIs.
• Smart home and IoT. Automatic light or climate control is the work of an API between the device and the control system.

What types of APIs and operating protocols exist?

There are several popular API architectures:

• REST API. The most common style. "Stateless" requests: each operation contains all the necessary information (e.g., authorization).
• RPC (Remote Procedure Call). Allows an application to execute remote functions as if they were local.
• SOAP. A more formal XML-based protocol. Still actively used in enterprise systems.

How do API integrations work?

Integration via API is like an open communication line between applications.

The process looks like this:

1. The server exposes data or functions via API.
2. The client application sends a request.
3. The server processes the request and returns a result.

For example: a taxi service accesses the maps API to determine the client's address, and the weather API to adjust the trip cost.

Modern Trends and API Security

Today, API is not just a tool, but a strategic technology:

• API Gateways. Control traffic, protect data, help test new application versions.
• Rate limiting. Protection against overloads and DDoS attacks.
• OAuth 2.0 and OpenID Connect. Authorization and authentication standards that allow working without transmitting passwords.
• JWT (JSON Web Tokens). A popular way to securely transmit data.
• OpenAPI Initiative. A unified API description language for ease of documentation and integrations.
• API Analytics. Monitoring and analyzing usage to improve performance and anticipate bottlenecks.

Conclusion

APIs are the foundation of the digital world. They enable applications to interact, automate business processes, and create new services.
Next time you pay for a purchase online or call a taxi, remember: APIs are behind it all.