API for Dummies: Learn the Basics of API

API stands for Application Programming Interface. Simply put, an API acts as a bridge that allows different software applications to communicate with each other. It defines a set of rules that enable one application to request and receive data or functionality from another.

In this API for dummies guide, we'll explore what APIs are, their purpose, and why they are important. We'll also discuss the different types of APIs, how to integrate them into your projects, and, finally, provide a hands-on tutorial on web scraping using Oxylabs Web Scraper API.

What are APIs?

At its core, an Application Programming Interface is a set of protocols and tools that allow different software applications to talk to each other.

Imagine you're at a restaurant: you (the client) place an order with the waiter (the API), who then communicates with the kitchen (the server) to get your food. Once the kitchen prepares your meal, the waiter brings it back to you. The waiter doesn’t need to know how the kitchen operates internally – only how to request and deliver the food.

Similarly, an API abstracts the complexity of the backend, providing a simple interface for applications to interact.

APIs work by defining endpoints – specific URLs or addresses where requests can be sent. When you interact with an API, you usually send a request, often in the form of HTTP methods like GET (to retrieve data), POST (to send data), PUT (to update data), or DELETE (to remove data).

The API processes your request and returns a response, usually in a structured format like XML or JSON format. Along with the response, the API provides an HTTP status code, which indicates whether the request was successful or if there was an error, such as "200 OK" for success or "404 Not Found" for missing data.

Modern applications rely heavily on APIs to function. When you book a flight online, check the weather on your phone, or log in to a website using your Google account, APIs are at work behind the scenes. They facilitate everything from fetching data to enabling complex integrations between different platforms and services.

As you become more familiar with APIs, you'll encounter terms like authentication, rate limiting, and API keys, which help ensure secure and efficient network communication between applications. Understanding how web APIs work is a crucial skill for any developer, as they enable you to connect different systems and leverage existing functionalities without reinventing the wheel.

What are APIs used for? Why are they important? 

APIs help different apps and systems communicate and share data, making modern technology more connected and automated. They power everything from weather apps to online payments, ensuring that different software can work together seamlessly.

A key use of APIs is retrieving data from external sources. Weather apps fetch real-time forecasts, financial platforms pull stock prices, and travel websites compare flights – all through APIs. Without API communication, developers would need to collect and update this data manually, making applications far less efficient. APIs also simplify user authentication, enabling logins with Google, Facebook, or Apple instead of creating new accounts. Similarly, they handle secure payment processing by allowing businesses to integrate services like PayPal, Stripe, or Square without managing sensitive payment details themselves.

APIs are also essential for interacting with operating systems – things like copy-pasting text, opening files, or adjusting settings all rely on them. More broadly, APIs enable automation, helping businesses streamline tasks like syncing customer data, updating inventories, or integrating marketing tools without manual input. This makes operations faster and reduces errors.

There are different types of APIs, including private APIs, which are used internally within a company, and public APIs, which are available for developers outside an organization to use. Additionally, partner APIs are shared with specific business partners to enable seamless interaction between services.

Beyond functionality, APIs are a valuable business asset. Companies offer different APIs as paid services – such as Google Maps for navigation or Stripe for payments – allowing developers to build on top of them while generating revenue. Many companies also provide an API client library to make it easier for developers to integrate their APIs into applications.

Ultimately, APIs are the backbone of today’s digital world. They enable apps, websites, and devices to communicate and forward data exchange, keeping everything connected and running smoothly. 

Types of APIs

APIs come in different types, each designed for specific use cases. Some APIs focus on web communication, while others interact with different software systems, databases, or hardware. Below are some of the most common types of APIs and how they function.

REST (Representational State Transfer) API

REST APIs are the most widely used APIs for web development. They follow a stateless architecture, meaning each API call from a client contains all the necessary information without relying on previous API requests. REST APIs use standard HTTP methods like GET, POST, PUT, and DELETE and typically return data in JSON or XML format. They are widely adopted because they are simple, scalable, and easy to integrate. REST APIs are commonly used in applications where the API server processes requests and interacts with a web server to deliver content to users.

SOAP (Simple Object Access Protocol) API

Simple Object Access Protocol (SOAP) APIs use an XML-based protocol to enable structured communication between systems. Unlike REST, SOAP APIs follow strict standards and include built-in security features, making them popular in industries like finance and healthcare where security and reliability are critical. However, SOAP APIs are more complex and require more bandwidth, making them slower compared to REST APIs. SOAP is often used when applications need to exchange data securely between different systems.

GraphQL API

GraphQL is a modern alternative to REST that allows clients to request only the data they need instead of receiving a fixed structure. This flexibility reduces unnecessary data transfer, making GraphQL APIs more efficient, especially for applications that deal with large or complex data sets. It is often used in mobile apps and interactive web applications where performance is key.

WebSocket API

WebSocket APIs provide real-time, two-way communication between clients and servers. Unlike REST and SOAP, which require repeated requests to update data, WebSockets maintain an open connection, allowing instant updates. They are often used in cases where rapid exchange of data is necessary – for example, in chat applications, online gaming, financial trading platforms, and live notifications.

Operating System APIs

Operating system (OS) APIs allow applications to interact with the underlying OS, enabling tasks like file management, device control, and process execution. Windows, macOS, and Linux each provide system APIs that developers can use to create software that works with the OS’s built-in software components.

Database APIs

Database APIs let applications communicate with database management systems (DBMS). These APIs allow developers to retrieve, update, and manage data efficiently using structured queries. Common examples include SQL-based APIs like JDBC (Java Database Connectivity) and ODBC (Open Database Connectivity), which allow software to interact with relational databases.

Hardware APIs

Hardware APIs enable software to control physical devices like printers, cameras, GPUs, and IoT sensors. These APIs are crucial for applications that need to interact with external hardware, such as image processing software using a graphics card API or a smartphone app accessing the camera.

Remote Procedure Calls (RPCs)

RPC APIs allow a program to execute code on a remote server as if it were a local function call. They are designed for high-performance applications where speed and efficiency are critical. Examples include gRPC (Google’s RPC framework), which is widely used for microservices and distributed systems.

API types comparison

Whether building a web app, integrating a database, working with hardware, or optimizing real-time communication, APIs play a crucial role in modern software development – down below, you can see each APIs type’s key feature.

Then, you will need to install prerequisites. The requests library is necessary to send HTTP requests to the API.

pip install requests

Import libraries and create a payload:

import json
import requests
from pprint import pprint


payload = {
    'source': 'google_search',
    'query': 'what is an API?',
    'pages': 2,
    'parse': True,
    # Add more parameters if needed.
}

The script imports three Python libraries:

json –  used to handle and save JSON data.

requests – sends HTTP requests to the API.

pprint – can be used to format API responses for readability.

The payload defines the API request parameters. In our code, the API will search Google for "what is an API?", retrieve 2 pages of results, and return parsed structured data. You can modify the parameters to fit different search queries or sources – whatever you think will fit your web scraping project needs best.

Next, submit a request:

response = requests.post(
    'https://realtime.oxylabs.io/v1/queries',
    auth=('USERNAME', 'PASSWORD'),
    json=payload,
)

Here, replace the USERNAME and PASSWORD with your own credentials for authentication.  

Lastly, save results to a JSON file:

with open('results.json', 'w') as f:
    json.dump(response.json(), f, indent=4)

This part of the code converts the API response to a human-readable format which can then be opened and analyzed using any text editor or JSON viewer.

Complete code sample

In this example, we’re making an API call to fetch Google search results, but the same method can be applied to different APIs for scraping product listings, job postings, or news articles. Here's the code for easy copy-pasting:

import json
import requests
from pprint import pprint


# Define API parameters.
payload = {
    'source': 'google_search',
    'query': 'what is an API?',
    'pages': 2,
    'parse': True,
    # Add more parameters if needed.
}

# Submit your request via the Real-time integration method.
response = requests.post(
    'https://realtime.oxylabs.io/v1/queries',
    auth=('USERNAME', 'PASSWORD'),
    json=payload,
)

# Save all results to a JSON file.
with open('results.json', 'w') as f:
    json.dump(response.json(), f, indent=4)

Conclusion

APIs (Application Programming Interface) are the backbone of modern technology, enabling seamless communication between applications, automating processes, and making data more accessible. Whether you're retrieving real-time weather data, integrating secure payment gateways, or automating workflows, APIs play a role in keeping everything connected.