What is an API call?

The full form of the API is Application programming interface Basically an API call is request by a software application to access data or any other service from another application or any other server. API calls are essential for enabling communication and data exchange between different software systems often over the internet. The APIs define a set of rules and protocols for interacting with a service and enabling different software systems to communicate with each other. API calls are fundamental in modern web development allowing applications to fetch data, perform operations and interact with external services. In this article we explain about what is an API call with related examples for your reference.

Prerequisites

• Node JS NPM
• React js
• Axios
• JavaScript
• API Endpoint

These are the following topics that we are going to discuss:

What is an API Call?

An API call is a request made by a client to an API endpoint on a server to retrieve or send information. It is a way for different applications to communicate with each other the client makes the request and the server sends back a response.

Below we provide examples for API call with different methods.

1. GET Request

GET /api/users

2. POST Request

POST /api/users
{
  "name": "John Doe",
  "email": "[email protected]"
}

3. PUT Request

PUT /api/users/1
{
  "email": "[email protected]"
}

4. DELETE Request

DELETE /api/users/1

Where Does an API Call Go?

An API call goes to a specific endpoint on a server. The endpoint is a URL that is part of the API and corresponds to a resource or an action. The server processes the request and sends back a response usually in the form of JSON or XML.

How Do API Calls Work?

• Client Request: The Client sends a HTTP request to the server. This request include
  • Method: Indicates the type of action to be performed like GET, POST, DELETE, PUT.
  • Endpoint: The URL to which the request is being sent.
  • Headers: Provides metadata for the request like token and other information.
  • Body: Contains data being sent to the server
• Server Processing: The Server receives the request, process it and perform the required action.
• Server Response: The Server sends back a response to the client. This response includes
  • Status Code: Indicates the success or Failure of the request like 200 OK or 400 NOT FOUND.
  • Headers: Provide metadata about the response.
  • Body: Contains the data being sent back to the client.

How Can API Calls Be Used for an Attack?

• Injection Attacks: Attackers inject malicious code into the API request to manipulate the servers execution.
• DDoS Attacks: Attackers overwhelm the server with a high volume of requests, causing a denial of service.
• Authentication Bypass: Exploiting vulnerabilities to bypass authentication mechanisms.
• Data Exposure: Exploiting insecure endpoints to access sensitive data.
• Parameter Tampering: Modifying request parameter to gain unauthorized access or perform unauthorized actions.

How to Secure APIs from Invalid API Calls

• Authentication and Authorization: Ensure that only authorized users can access the API.
• Input Validation: Validate all inputs to prevent injection attacks.
• Rate Limiting: Limit the number of requests a client can make in a given time period.
• HTTPS: Use HTTPS to encrypt data transmitted between the Client and server.
• API Gateway: Use an API gateway to manage and monitor API traffic.
• Error Handling: Provide informative but secure error messages.
• Token Expiry: Use token that expire after a certain period to reduce the risk of token theft.

The Importance of API Management with Diagram

API management is crucial for several reasons. Below we provide that information for your reference.

• Security: Protects APIs from unauthorized access and attacks.
• Monitoring: Tracks usage and performance of APIs.
• Scalability: Ensures APIs can handle increased load.
• Versioning: Manages different versions of APIs to support backward compatibility.
• Documentation: Provides comprehensive documentation for developers.
• API Client: The Client making the API call.
• API Gateway: Manages and routes API requests, providing, providing security, rate limiting and monitoring.
• API Service: The server side logic that processes the API requests.
• Database: Stores and Retrieves data as required by the API service.
  

This is one of the approach for API call. The REST is an architectural style that uses standard HTTP methods such as GET, POST, PUT, DELETE to interact with resources represented by URLs.

Note:

Here we use https://jsonplaceholder.typicode.com/users. This URL is part of the JSONPlaceholder API which is a free online REST API that you can use for testing and prototyping. JSONPlaceholder provides various endpoints that return fake data, making it an ideal tool for developers to practice making API calls without needing to set up a backend server. Here by using REST API call we got the fake users data. From this URL we fetch user id, username and user email by using REST API call.

Example Using REST API

Step 1: Create a React Project

First we need to create a React Project by using npm commands. Below we provide those commands to create a React Project with outputs for reference.

npx create-react-app project-name

Step 2: Install Axios

Once Project is successfully created, Now redirect project folder and install Axios for communicate with APIs.

cd project-namen
pm install axios

Step 3: Open Project Folder

Now we open this project through VS Code editor. After this we develop the required logic for creating REST API call in the App.js file which is located in the src folder of project

Step 4: Implement REST API

Once everything is setup, Now we created a logic for REST API call in the App.js file. Below we provide that source code for your reference.

// App.js
import React, { useState, useEffect } from 'react';
import axios from 'axios';

function App() {
  const [users, setUsers] = useState([]);

  useEffect(() => {
    // Make an API call using Axios
    axios.get('https://jsonplaceholder.typicode.com/users')
      .then(response => {
        setUsers(response.data);
      })
      .catch(error => {
        console.error('There was an error making the API call!', error);
      });
  }, []);

  return (
    <div className="App">
      <div>
        <h1>Users</h1>
        <ul>
          {users.map(user => (
            <li key={user.id}>{user.name} - {user.email}</li>
          ))}
        </ul>
      </div>
    </div>
  );
}

export default App;

Step 5: Run the Application

Once business logic is developed now we need to run the project by using below command. If application ran successfully got http://localhost:3000

npm start

Step 6: Output

Once application running successfully, Then got this URL for to see the output.

http://localhost:3000/