Auto Routing & Your First Endpoint

In this section, we enable CodeIgniter's Improved Auto Routing feature and create a simple JSON endpoint to confirm everything is wired correctly.

Why Auto-Routing?

The previous tutorial showed how to define routes manually in app/Config/Routes.php. While powerful and flexible, this can be tedious for RESTful APIs with many endpoints that follow a common pattern. Auto-Routing simplifies this by mapping URL patterns to controller classes and methods based on conventions, and its focus on HTTP verbs works well for RESTful APIs.

Enable Improved Auto Routing

By default, Auto-Routing is turned off. Enable it so your controllers automatically handle REST-style methods.

Open app/Config/Feature.php and confirm this flag is true (this is the default):

public bool $autoRoutesImproved = true;

The "Improved" auto router is more secure and reliable than the legacy version, so it's recommended for all new projects.

Then, in app/Config/Routing.php, confirm auto-routing is enabled:

public bool $autoRoute = true;

That's all you need for CodeIgniter to automatically map your controller classes to URIs like GET /api/ping or POST /api/ping.

Create a Ping Controller

To understand how a basic API endpoint works, let's generate a controller to serve as our first API endpoint. This will provide a simple "ping" response to confirm our setup is correct.

php spark make:controller Api/Ping

This creates app/Controllers/Api/Ping.php.

Edit the file so it looks like this:

<?php

namespace App\Controllers\Api;

use App\Controllers\BaseController;
use CodeIgniter\API\ResponseTrait;
use CodeIgniter\HTTP\ResponseInterface;

class Ping extends BaseController
{
    use ResponseTrait;

    public function getIndex(): ResponseInterface
    {
        return $this->respond(['status' => 'ok'], 200);
    }
}

Here we:

• Use the ResponseTrait, which already includes REST helpers such as respond() and proper status codes.
• Define a getIndex() method. The get prefix means it responds to GET requests, and the Index name means it matches the base URI (/api/ping).

Test the route

Start the development server if it isn't running:

php spark serve

Now visit:

• Browser: http://localhost:8080/api/ping
• cURL: curl http://localhost:8080/api/ping

Expected response:

{
    "status": "ok"
}

Congratulations — that's your first working JSON endpoint!

Understand how it works

When you request /api/ping:

1. The Improved Auto Router finds the App\Controllers\Api\Ping class.
2. It detects the HTTP verb (GET).
3. It calls the corresponding method name: getIndex().
4. ResponseTrait provides helper methods to produce consistent output.

Here's how other verbs would map if you added them later:

HTTP Verb	Method Name
GET /api/ping	getIndex()
POST /api/ping	postIndex()
DELETE /api/ping	deleteIndex()

Content Negotiation with the Format Class

The ResponseTrait uses CodeIgniter\Format\Format to format response data. When its $format property is null, it negotiates a supported format from the request's Accept header.

The default $format is 'json'. Set it to 'xml' for XML responses, or to null for content negotiation. This tutorial keeps the default JSON format:

<?php

namespace App\Controllers\Api;

use App\Controllers\BaseController;
use CodeIgniter\API\ResponseTrait;
use CodeIgniter\HTTP\ResponseInterface;

class Ping extends BaseController
{
    use ResponseTrait;

    public function getIndex(): ResponseInterface
    {
        return $this->respond(['status' => 'ok'], 200);
    }
}

Optional: Return More Data

The respond() method can return additional data:

<?php

namespace App\Controllers\Api;

use App\Controllers\BaseController;
use CodeIgniter\API\ResponseTrait;
use CodeIgniter\CodeIgniter;
use CodeIgniter\HTTP\ResponseInterface;

class Ping extends BaseController
{
    use ResponseTrait;

    public function getIndex(): ResponseInterface
    {
        return $this->respond([
            'status'  => 'ok',
            'time'    => date('c'),
            'version' => CodeIgniter::CI_VERSION,
        ]);
    }
}

You now have a working endpoint tested in both the browser and cURL. In the next section, we'll create our first real database resource. You'll define a migration, seeder, and model for a simple books table that powers the API's CRUD endpoints.