<?php

namespace AppBundle\Controller;

use AppBundle\Controller\API\Listing\OverviewController;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Request;

class StartpageController extends Controller
{
    /**
     * @Route("/", name="startpage")
     */
    public function indexAction(Request $request)
    {
        $oc = $this->get('app.api.listing.overview');
        $overview = $oc->execute('1.0');

        return $this->render('startpage/index.html.twig', ['type' => 'startpage', 'overview' => $overview, 'title' => 'Welcome']);
    }
}

<?php

namespace AppBundle\Controller;

use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Request;

class StartpageController extends Controller
{
    /**
     * @Route("/", name="startpage")
     */
    public function indexAction(Request $request)
    {
        // replace this example code with whatever you need
        return $this->render('startpage/index.html.twig', ['type' => 'startpage']);
    }
}

--- 
+++ 
@@ -2,6 +2,7 @@
 
 namespace AppBundle\Controller;
 
+use AppBundle\Controller\API\Listing\OverviewController;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
 use Symfony\Bundle\FrameworkBundle\Controller\Controller;
 use Symfony\Component\HttpFoundation\Request;
@@ -13,7 +14,9 @@
      */
     public function indexAction(Request $request)
     {
-        // replace this example code with whatever you need
-        return $this->render('startpage/index.html.twig', ['type' => 'startpage']);
+        $oc = $this->get('app.api.listing.overview');
+        $overview = $oc->execute('1.0');
+
+        return $this->render('startpage/index.html.twig', ['type' => 'startpage', 'overview' => $overview, 'title' => 'Welcome']);
     }
 }
Call listing/overview service from startpage
