REST API, is CI for me?

Just came across CodeIgniter this morning and I am intrigued by it, I am wondering if I could use it to "improve" upon my manual coding of php "REST" functions like the following?

PHP Code:

<?php
 
require_once 'DB_Functions.php';
$db = new DB_Functions();

$response = array("error" => FALSE);

if (isset($_POST['id'])) {

    $id = $_POST['id'];
$price = $_POST['price'];
$clientid = $_POST['clientid'];

if ($db->isCheckedOut($clientid) == false)
{ 
$result = $db->addToCart($id, $clientid, $price);

echo json_encode($result);
}
else
{
$result = "invalid";
echo json_encode($result);
}
}
?>

I am calling it in a mobile app using ajax:

Code:

function addToCart($menuID, $price, $clientID)
{
var dataString = "id=" + $menuID + "&price=" + $price + "&clientid=" + $clientID;
$.ajax({
type: "POST",
url: serviceURL + "addToCart.php",
data: dataString,
crossDomain: true,
cache: false,
success: function(data) {

From my initial understanding, CI seems to be a "complete" package where I could create my "frontend" and "backend", is that correct? Could I not use it for "backend" purposes only? Like exposing a "Web Service" or "REST" API that I could call either in mobile or a "web" application?

TIA

Good grief, yes! (to both questions)

Simpler is always better

Yes, you don't need to have a front-end. It could just be an API. I would suggest that you have a go with CodeIgniter 4 RC4, as it provides a nice way of building RESTful routes.
https://codeigniter4.github.io/userguide...stful.html

Thank you guys, I need to wrap my head on this, looks like there is a learning curve involved as of now. Are there any downloadable sample projects out there?

Lonnie has lots of sample projects one of them is a CI 4 Myth::Auth

You can find his projects here: Lonnie's GitHub

What did you Try? What did you Get? What did you Expect?

Joined CodeIgniter Community 2009.  ( Skype: insitfx )