The PagerfantaBundle provides support for serializing Pagerfanta/Pagerfanta instances using either the Symfony Serializer component or the JMS Serializer (note, the JMSSerializerBundle must be installed to enable the serialization handler for the JMS serializer).

Below is an example of building a JSON response in a controller using the Symfony Serializer:

<?php

namespace App\Controller\API;

use App\Entity\BlogPost;
use Pagerfanta\Doctrine\ORM\QueryAdapter;
use Pagerfanta\Pagerfanta;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\JsonResponse;
use Symfony\Component\Routing\Annotation\Route;

final class PostController extends AbstractController
{
    /**
     * @Route("/api/posts", name="app_api_post_list", methods={"GET"})
     */
    public function apiPostList(): JsonResponse
    {
        $queryBuilder = $this->get('doctrine')->getRepository(BlogPost::class)->createBlogListQueryBuilder();

        $pagerfanta = new Pagerfanta(
            new QueryAdapter($queryBuilder)
        );

        return $this->json($pagerfanta);
    }
}

Below is an example of how a Pagerfanta\Pagerfanta instance is serialized into JSON format (note the items array is a simplified example, it will be an array of items based on your serializer configuration):

{
    "items": [
        {
            "id": 1
        },
        {
            "id": 2
        },
        {
            "id": 3
        }
    ],
    "pagination": {
        "current_page": 1,
        "has_previous_page": false,
        "has_next_page": true,
        "per_page": 10,
        "total_items": 35,
        "total_pages": 4
    }
}