Build a Simple PHP API – Step-by-Step (REST API for Beginners)

APIs power modern applications. In this guide, you’ll build a simple REST API using PHP from scratch.

No frameworks — just pure PHP 🔥

🔹 Project Structure

api/
 ├── index.php
 └── db.php

🔹 Database Connection (db.php)

<?php
$pdo = new PDO("mysql:host=localhost;dbname=test", "root", "password");
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

🔹 Basic API (index.php)

<?php
header("Content-Type: application/json");
require 'db.php';

$method = $_SERVER['REQUEST_METHOD'];

if ($method === 'GET') {
    $stmt = $pdo->query("SELECT * FROM users");
    echo json_encode($stmt->fetchAll(PDO::FETCH_ASSOC));
}

🔹 Add POST Endpoint

if ($method === 'POST') {
    $data = json_decode(file_get_contents("php://input"), true);

    $stmt = $pdo->prepare("INSERT INTO users (name) VALUES (?)");
    $stmt->execute([$data['name']]);

    echo json_encode(["status" => "success"]);
}

🔹 Test API

Use curl:

curl http://localhost/api

POST request:

curl -X POST http://localhost/api \
-H "Content-Type: application/json" \
-d '{"name":"Ward"}'

🔹 Improve Your API

• Add validation
• Handle errors
• Use routing
• Add authentication (JWT)

🔹 Example JSON Response

[
  {
    "id": 1,
    "name": "Ahmad"
  }
]

🔹 Security Tips

• Sanitize input
• Use prepared statements (already done ✅)
• Add rate limiting

🔹 Conclusion

Now you can:

• Build APIs with PHP
• Connect frontend apps
• Scale into full backend systems