Description UUIDs are automatically serialized/deserialized as expected. Syntax // src/Entity/Product.php namespace App\Entity; use Doctrine\ORM\Mapping as ORM; /** * @ORM\Entity(repositoryClass="App\Repository\ProductRepository") */ class Product { /** * @ORM\Column(type="uuid") */ private $id; // ... } $product = new Product(); $jsonContent = $serializer->serialize($product, 'json'); // $jsonContent contains {"id":"9b7541de-6f87-11ea-ab3c-9da9a81562fc","...":"..."}