Why does Google need the Identifiers?
Google wants to understand exactly which products you are selling. If they are able to identify each product, they can
- match it with search queries
- compare it with the same products (of other merchants) on Google Shopping
The best way to compare products, is to compare their unique identifiers, like Brand, GTIN and MPN.
Identifier exists (or not)
So first, Google wants to know if unique identifiers, like GTIN and MPN actually exist for your products. For most products that are manufactured, they do exist indeed. So you set the 'identifier exist' to True.
Only for Custom goods you can set it to false: Custom goods are unique products that are hand crafted or no longer manufactured. Examples are hand knitted sweaters or antique furniture or vintage items.
Setting it to 'False' for products that do have an identifier will not work; Google will disapprove those products or even suspend your account.
Brand, MPN and GTIN - What is required?
Let's take a closer look at these 3 unique identifiers:
The brand name of each product. Google requires you to add this field to your feed in all cases. The only exception is for custom-made items where you have set the 'identifier exist' field to 'false'. But you might as well add your own brand if you offer custom made products.
MPN is a unique identifier issued by the manufacturer. If you have the GTIN in your feed, the MPN is not mandatory. Without GTIN, Google does require you to add MPN & Brand. The exception for custom goods applies here as well.
GTIN is the numerical version of the bar code. It is called UPC in the US and EAN in Europe. A unique ID according to international standards. GTIN is an identifier that is created by GS1, an international non-profit organization.
Google has a database with most of the world's GTINs. If you include the GTIN for each product in your feed, Google can identify each product and knows all product specs exactly. Also: if you provide the wrong GTIN, Google will know instantly and they will disapprove that product.
GTINs are required in Australia, Brazil, the Czech Republic, France, Germany, Italy, Japan, the Netherlands, Spain, Switzerland, the UK and the US.
What if you don't have Brand?
A field for Brand is often easy to create:
All products have the same brand
You just add that one brand for all products:
Map Brand from Title or Description
If the Brand is mentioned in the Title or the Description or another field, so you map it from there:
What if you don't have MPN?
There is an easy way to get around that problem: Map your MPN from SKU or Variant ID or another field that contains a unique identifier per product. It won't be an official MPN then, but Google usually accepts it.
What if you don't have GTIN?
There is no workaround and adding the right GTIN for each product is the only option. You can ask your supplier or the manufacturer, check or scan the barcode on your products or visit a GTIN-database to look up the right GTINs. Here's More info on finding your GTINs.