Building APIs is at the heart of modern web development. Whether you're powering a mobile app, a frontend framework, or a third-party integration, a well-designed API makes all the difference. This approach fits perfectly into API-first development philosophy where you build the backend before worrying about clients.

The Foundation: Routing

Every good API starts with clean routing. Here's a simple router structure:

$router->get('/api/users', getUsersHandler(...));
$router->post('/api/users', createUserHandler(...));
$router->get('/api/users/:id', getUserHandler(...));

Keep it RESTful. Use HTTP methods intentionally. GET for reading, POST for creating, PUT for updating, DELETE for... well, deleting.

Type-Safe Request Handling

With PHP 8.4's modern features like strict types and property promotion, you can build type-safe request handlers:

function createUser(Request $request): Response {
    $data = $request->validate([
        'name' => 'required|string|max:100',
        'email' => 'required|email',
    ]);

    $user = User::create($data);

    return Response::json($user, 201);
}

JSON All The Things

Modern APIs speak JSON. Make sure your responses are consistent:

return Response::json([
    'success' => true,
    'data' => $user,
    'message' => 'User created successfully',
], 201);

Include proper HTTP status codes. They're not just suggestions—they're part of the contract.

Security First

Never trust user input. Validate everything. Sanitize everything. Escape everything.

  • Use prepared statements for database queries
  • Implement rate limiting
  • Add authentication (JWT, OAuth, API keys — see Spring Security JWT patterns for auth concepts)
  • Always use HTTPS in production

Error Handling

When things go wrong (and they will), be helpful:

try {
    $user = User::findOrFail($id);
} catch (ModelNotFoundException $e) {
    return Response::json([
        'success' => false,
        'message' => 'User not found',
    ], 404);
}

Testing

Test your endpoints. Use PHPUnit or Pest. Mock external services. Make testing easy, and you'll actually do it.

test('creates a user via API', function () {
    $response = $this->post('/api/users', [
        'name' => 'John Doe',
        'email' => 'john@example.com',
    ]);

    $response->assertStatus(201);
    $response->assertJson(['success' => true]);
});

Documentation

Document your API. Use OpenAPI/Swagger, or even just a well-maintained README. Future you (and your teammates) will appreciate it.

Building APIs is both an art and a science. Get the basics right, and the rest falls into place. For more robust enterprise solutions, check out building REST APIs with Spring Boot and Kotlin. For serverless deployments, see Lambda-based APIs with Node.js.