invoiceninja/app/controllers/PaymentApiController.php

<?php

use ninja\repositories\PaymentRepository;

class PaymentApiController extends Controller
{
    protected $paymentRepo;

    public function __construct(PaymentRepository $paymentRepo)
    {
        $this->paymentRepo = $paymentRepo;
    }

    public function index()
    {
        $payments = Payment::scope()->orderBy('created_at', 'desc')->get();
        $payments = Utils::remapPublicIds($payments->toArray());

        $response = json_encode($payments, JSON_PRETTY_PRINT);
        $headers = Utils::getApiHeaders(count($payments));

        return Response::make($response, 200, $headers);
    }

  /*
  public function store()
  {
    $data = Input::all();
    $invoice = $this->invoiceRepo->save(false, $data, false);

    $response = json_encode($invoice, JSON_PRETTY_PRINT);
    $headers = Utils::getApiHeaders();
    return Response::make($response, 200, $headers);
  }
  */
}