So, I have a custom product attribute: $eavSetup->addAttribute('catalog_product', 'visible_in_country', [ 'type' => 'varchar', 'backend_type' => 'text', 'backend_model' => MagentoEavModelEntityAttributeBackendArrayBackend::class, 'input' => 'multiselect', 'searchable' => true, 'filterable' => true, 'filterable_in_search' => false, ... ]); In Elasticsearch, the values of the attribute are saved as a string and as an array: { […]