Getting Started with PHP: Building RESTful APIs

By Alessandro D.P.3 min readMarch 2, 2026

Understanding RESTful APIs

REST (Representational State Transfer) is an architectural style that uses standard HTTP methods to manage resources. The primary HTTP methods used in RESTful APIs are:

GET: Retrieve data from the server.
POST: Send data to the server to create a new resource.
PUT: Update existing resources.
DELETE: Remove resources.

Setting Up Your PHP Environment

To start building a RESTful API, ensure you have a PHP environment set up. You can use tools like XAMPP, MAMP, or a cloud-based server. For this tutorial, we will use a simple file-based structure.

Create Project Directory: Create a folder named rest_api in your web server's root directory.
Create an index.php File: This will serve as the entry point for your API.

Basic API Structure

Here's a basic structure for your index.php file:

<?php
header("Content-Type: application/json; charset=UTF-8");

$requestMethod = $_SERVER["REQUEST_METHOD"];
$uri = explode('/', trim($_SERVER['PATH_INFO'], '/'));

switch ($requestMethod) {
    case 'GET':
        // Handle GET requests
        break;
    case 'POST':
        // Handle POST requests
        break;
    case 'PUT':
        // Handle PUT requests
        break;
    case 'DELETE':
        // Handle DELETE requests
        break;
    default:
        http_response_code(405);
        echo json_encode(["message" => "Method Not Allowed"]);
        break;
}
?>

Implementing CRUD Operations

Let’s implement basic CRUD operations for a users resource.

Sample Data

For simplicity, we will use an array to simulate a database:

$users = [
    ["id" => 1, "name" => "Alice", "email" => "[email protected]"],
    ["id" => 2, "name" => "Bob", "email" => "[email protected]"],
];

Handling GET Requests

To retrieve user data, implement the following code under the GET case:

case 'GET':
    if (isset($uri[1])) {
        $id = intval($uri[1]);
        $user = array_filter($users, fn($u) => $u['id'] === $id);
        echo json_encode(array_values($user));
    } else {
        echo json_encode($users);
    }
    break;

Handling POST Requests

To create a new user, add the following code under the POST case:

case 'POST':
    $input = json_decode(file_get_contents('php://input'), true);
    $newUser = [
        "id" => count($users) + 1,
        "name" => $input['name'],
        "email" => $input['email'],
    ];
    $users[] = $newUser;
    echo json_encode($newUser);
    break;

Handling PUT Requests

To update an existing user, include this code under the PUT case:

case 'PUT':
    $id = intval($uri[1]);
    $input = json_decode(file_get_contents('php://input'), true);
    foreach ($users as &$user) {
        if ($user['id'] === $id) {
            $user['name'] = $input['name'];
            $user['email'] = $input['email'];
            echo json_encode($user);
            break;
        }
    }
    break;

Handling DELETE Requests

To delete a user, add this code under the DELETE case:

case 'DELETE':
    $id = intval($uri[1]);
    foreach ($users as $key => $user) {
        if ($user['id'] === $id) {
            unset($users[$key]);
            echo json_encode(["message" => "User deleted"]);
            break;
        }
    }
    break;

Complete API Code

Here is the complete index.php code:

<?php
header("Content-Type: application/json; charset=UTF-8");

$requestMethod = $_SERVER["REQUEST_METHOD"];
$uri = explode('/', trim($_SERVER['PATH_INFO'], '/'));

$users = [
    ["id" => 1, "name" => "Alice", "email" => "[email protected]"],
    ["id" => 2, "name" => "Bob", "email" => "[email protected]"],
];

switch ($requestMethod) {
    case 'GET':
        if (isset($uri[1])) {
            $id = intval($uri[1]);
            $user = array_filter($users, fn($u) => $u['id'] === $id);
            echo json_encode(array_values($user));
        } else {
            echo json_encode($users);
        }
        break;
    case 'POST':
        $input = json_decode(file_get_contents('php://input'), true);
        $newUser = [
            "id" => count($users) + 1,
            "name" => $input['name'],
            "email" => $input['email'],
        ];
        $users[] = $newUser;
        echo json_encode($newUser);
        break;
    case 'PUT':
        $id = intval($uri[1]);
        $input = json_decode(file_get_contents('php://input'), true);
        foreach ($users as &$user) {
            if ($user['id'] === $id) {
                $user['name'] = $input['name'];
                $user['email'] = $input['email'];
                echo json_encode($user);
                break;
            }
        }
        break;
    case 'DELETE':
        $id = intval($uri[1]);
        foreach ($users as $key => $user) {
            if ($user['id'] === $id) {
                unset($users[$key]);
                echo json_encode(["message" => "User deleted"]);
                break;
            }
        }
        break;
    default:
        http_response_code(405);
        echo json_encode(["message" => "Method Not Allowed"]);
        break;
}
?>

Best Practices

Use a Framework: For production applications, consider using a PHP framework like Laravel or Slim, which provides built-in support for routing and middleware.
Input Validation: Always validate and sanitize user input to prevent security vulnerabilities.
Error Handling: Implement comprehensive error handling to provide meaningful feedback to API consumers.
Versioning: Consider versioning your API (e.g., /api/v1/users) to manage changes over time.