APIs (Application Programming Interfaces) are the backbone of modern software development, allowing applications to communicate and share data seamlessly. While frameworks like Laravel and Symfony make API development easier, you can also build an API in PHP without a framework. This guide walks you through the process step-by-step, making it simple to understand even if you’re new to API development.

Why Build an API Without a Framework?

Building an API without a framework gives you complete control over the code and a deeper understanding of how APIs work. It’s an excellent exercise for PHP developers who want to hone their skills or create lightweight APIs for specific use cases.

Step 1: Set Up Your Environment

Before diving into coding, ensure your development environment is ready.

1. Install PHP: Make sure PHP is installed on your system. Use php -v in your terminal to check the version.
2. Set Up a Local Server: Use tools like XAMPP, WAMP, or the built-in PHP server (php -S localhost:8000).
3. Create a Project Folder: Organize your files. For example, create a folder named php-api to store your API code.

Step 2: Create the API Endpoint

An API endpoint is a URL that allows clients to interact with your API. Start by creating a basic structure:

1. Define the API entry point: Create a file named api.php in your project folder.
2. Set up routing: Use a $_SERVER global variable to handle different HTTP methods like GET, POST, PUT, and DELETE.

Here’s an example code snippet:

<?php  
header("Content-Type: application/json");  

$requestMethod = $_SERVER['REQUEST_METHOD'];  

switch ($requestMethod) {  
    case 'GET':  
        handleGetRequest();  
        break;  
    case 'POST':  
        handlePostRequest();  
        break;  
    default:  
        echo json_encode(["message" => "Method not allowed"]);  
        http_response_code(405);  
        break;  
}  

function handleGetRequest() {  
    echo json_encode(["message" => "This is a GET request"]);  
}  

function handlePostRequest() {  
    echo json_encode(["message" => "This is a POST request"]);  
}  
?>

Step 3: Connect to a Database

APIs often interact with databases to retrieve or store data. Let’s Connect to a MySQL database using PHP’s PDO (PHP Data Objects).

<?php  
function connectToDatabase() {  
    $host = 'localhost';  
    $db = 'example_db';  
    $user = 'root';  
    $pass = '';  

    try {  
        $pdo = new PDO("mysql:host=$host;dbname=$db", $user, $pass);  
        $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);  
        return $pdo;  
    } catch (PDOException $e) {  
        die(json_encode(["error" => "Database connection failed", "message" => $e->getMessage()]));  
    }  
}  
?>

Step 4: Add CRUD Operations

CRUD (Create, Read, Update, Delete) operations are the foundation of most APIs. Here’s how to implement them:

Create (POST): Add Data

function addData($pdo, $data) {  
    $sql = "INSERT INTO users (name, email) VALUES (:name, :email)";  
    $stmt = $pdo->prepare($sql);  
    $stmt->execute([":name" => $data['name'], ":email" => $data['email']]);  
    return ["message" => "Data added successfully"];  
}  

Read (GET): Fetch Data

function fetchData($pdo) {  
    $sql = "SELECT * FROM users";  
    $stmt = $pdo->query($sql);  
    return $stmt->fetchAll(PDO::FETCH_ASSOC);  
}

Update (PUT): Modify Data

function updateData($pdo, $id, $data) {  
    $sql = "UPDATE users SET name = :name, email = :email WHERE id = :id";  
    $stmt = $pdo->prepare($sql);  
    $stmt->execute([":name" => $data['name'], ":email" => $data['email'], ":id" => $id]);  
    return ["message" => "Data updated successfully"];  
}

Delete (DELETE): Remove Data

function deleteData($pdo, $id) {  
    $sql = "DELETE FROM users WHERE id = :id";  
    $stmt = $pdo->prepare($sql);  
    $stmt->execute([":id" => $id]);  
    return ["message" => "Data deleted successfully"];  
}

Step 5: Test Your API

Use tools like Postman or cURL to test your API endpoints.

• GET Request: http://localhost/php-api/api.php
• POST Request: Send a JSON payload like {"name": "John Doe", "email": "john@example.com"}.
• PUT and DELETE Requests: Include the resource ID and relevant data.

Conclusion

Creating an API in PHP without a framework helps you understand the fundamentals of backend development. By following these steps, you can build a lightweight, functional API tailored to your needs.

What’s Next?

• Add authentication for secure API access.
• Implement advanced features like pagination, filtering, or rate limiting.

Have questions about this tutorial? Leave a comment below or share your experiences with building APIs in PHP!