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REST API Development with PHP (Complete Beginner to Production Guide)

REST APIs are the backbone of modern web and mobile applications. They allow different systems to communicate with each other through standardized HTTP requests.

What is a REST API?

REST stands for Representational State Transfer. It is an architectural style used to design networked applications. REST APIs use HTTP methods such as GET, POST, PUT, and DELETE to interact with data.

Basic API Structure

A simple REST API in PHP typically follows this structure:

/api
  users.php
  products.php
  auth.php

Example: Simple GET Endpoint

header('Content-Type: application/json');

$data = [
    'status' => 'success',
    'message' => 'API working'
];

echo json_encode($data);

Handling HTTP Methods

$method = $_SERVER['REQUEST_METHOD'];

if($method == 'GET'){
   // fetch data
}

if($method == 'POST'){
   // create data
}

Connecting to Database

$conn = new mysqli("localhost","user","password","database");

Always sanitize inputs and use prepared statements when inserting or retrieving data.

Authentication

Production APIs usually use authentication such as:

  • API Keys
  • JWT Tokens
  • OAuth

Security Best Practices

  • Validate all input
  • Use HTTPS
  • Limit API request rate
  • Return proper HTTP status codes

Example JSON Response

{
 'status':'success',
 'data':[
   {'id':1,'name':'John'},
   {'id':2,'name':'Anna'}
 ]
}

Conclusion: REST APIs allow applications to scale and integrate with mobile apps, third-party services, and microservices architecture.