Build a Simple REST API in PHP (GET + POST)

Let’s build a small API endpoint in PHP that returns and creates posts.

Goal endpoints

• GET /api/posts
• POST /api/posts

Step 1: Simple router using REQUEST_METHOD

File: api.php

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

$method = $_SERVER['REQUEST_METHOD'];

if ($method === 'GET') {
  $rows = $pdo->query("SELECT id, title, body FROM posts ORDER BY id DESC")->fetchAll();
  echo json_encode($rows);
  exit;
}

if ($method === 'POST') {
  $input = json_decode(file_get_contents("php://input"), true);
  $title = trim($input['title'] ?? '');
  $body = trim($input['body'] ?? '');

  if ($title === '' || $body === '') {
    http_response_code(400);
    echo json_encode(["error" => "title and body are required"]);
    exit;
  }

  $stmt = $pdo->prepare("INSERT INTO posts (title, body) VALUES (:title, :body)");
  $stmt->execute(["title" => $title, "body" => $body]);

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

http_response_code(405);
echo json_encode(["error" => "Method not allowed"]);
?>

Why we used php://input

When clients send JSON, it does not appear in $_POST. You read raw body and decode it.

Next: Security basics, XSS and CSRF protection in PHP forms.