? Types of APIs

? Quick Overview

APIs (Application Programming Interfaces) allow different software systems to communicate with each other. The most commonly used API styles are REST, SOAP, and GraphQL. Each follows a different architectural approach and is suited for different use cases.

? Key Concepts

• API – A contract that defines how software components interact
• Client – Application requesting data
• Server – Application providing data
• Endpoint – URL that accepts requests
• HTTP Methods – GET, POST, PUT, DELETE

? Syntax / Theory

? REST API

REST (Representational State Transfer) uses standard HTTP methods and works with resources identified by URLs. It is lightweight and typically uses JSON.

? SOAP API

SOAP (Simple Object Access Protocol) is a strict, XML-based protocol with built-in security and standards. It is commonly used in enterprise systems.

? GraphQL API

GraphQL allows clients to request exactly the data they need in a single request, reducing over-fetching and under-fetching of data.

? Code Example(s)

// REST API GET request using Fetch API
fetch("https://api.example.com/users")
.then(response => response.json())
.then(data => console.log(data));

// SOAP request body sent via HTTP
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
<soapenv:Body>
<getUserDetails />
</soapenv:Body>
</soapenv:Envelope>

// GraphQL query requesting specific fields
query {
users {
id
name
email
}
}

? Live Output / Explanation

? Interactive Example

Click the buttons below to simulate a request to a server. Observe the difference in how the request looks and how the data is returned.

Select a simulation above...

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? Use Cases

• REST – Web & mobile applications
• SOAP – Banking, payment gateways, enterprise apps
• GraphQL – Modern SPAs, mobile apps with complex data needs