shopify: Getting product's current category ID via API

Question

You can easily select a taxonomy category ID via the UI:

However, where can you read this ID via the API? I've retrieved the product before and after a category change, and the only thing that changes is the updated_at value. I've compared all associated metafields, and nothing changes there, either.

Answer 1

It is only accessible via GraphQL queries. It is under the category field:

query {                                                                         
  product(id: "gid://shopify/Product/<product_id>") {                         
    productType                                                                 
    category {                                                                  
      name                                                                      
      id                                                                        
    }                                                                           
  }                                                                             
}

Response:

{
    'data': {
        'product': {
            'productType': 'Insulated Jackets', 
            'category': {
                'name': 'Trucker Jackets', 
                'id': 'gid://shopify/TaxonomyCategory/aa-1-10-2-14'
            }
        }
    }, 

    'extensions': {
        'cost': {
            'requestedQueryCost': 2, 
            'actualQueryCost': 2, 
            'throttleStatus': {
                'maximumAvailable': 20000.0, 
                'currentlyAvailable': 19998, 
                'restoreRate': 1000.0
            }
        }
    }
}