In API Platform or in Symfony, If you use a denormalization like this : use Symfony\Component\Serializer\Normalizer\NormalizerInterface; private NormalizerInterface $normalizer; $this->normalizer = $normalizer; $this->normalizer->denormalize($data, Object::class) You need to change it to a denormalizerInterface like this use Symfony\Component\Serializer\Normalizer\DenormalizerInterface; private DenormalizerInterface $denormalizer; $this->denormalizer…