Google Merchant Center

Why Is the Product ID Attribute So Important for Product Feeds? (+Practical Tips)

0 · by Dennis Moons · Updated on 23 March 2023

Google needs a unique reference number tied to a specific product to process product data. Each SKU in your feed inventory has one, so you better double-check the product ID before making any changes.

In this article, we will cover the product ID attribute; why it’s important, how Google uses it, whether it plays a role in product feed operations, tips on best practices, and other product ID essentials.

We’ll explain how that’s done, but first, let’s see what the product ID attribute is.

This article is part of our Google Product Feed hub.

What Is the Product ID Attribute in the Product Feed?

The ID attribute is used to identify a product. It serves as a reference to a specific trade item in your product feed and is helpful when you try to:

  • Track campaign performance of specific trade items
  • Set up bidding strategies
  • Set up a promotion for a group of products
  • Find a specific product (for whatever reason)

That being said, product IDs for items in your feed are not available to customers. The product ID is for internal use only, used to ensure product data is connected to one reference per each product.

Google creates product IDs automatically, so you probably won’t note them until you need to track the performance history of a specific item or make changes to product data in your feed.

Every single product has an ID, including product variants. For example, the same product available in two different colors will have two separate product IDs for each variation.

Is the [ID] Attribute Required?

Yes, the ID attribute is required for each product in the inventory. In fact, Google’s requirements for merchants are to have a separate product ID for each variation of the product (more on this below).

How Is Product ID Used in Google Shopping?

Product IDs are like SKUs, and they are used when Google, or data tools, need to process a product from your feed. The “ID” is a string of symbols that serves as a reference for a product.

They can be used “internally” within the Google Merchant Center, in your ad campaigns (especially Google Shopping and smart campaigns), to track user interactions with your product, and to process items with product feed tools. 

Each product ID is unique, but it’s not a unique product identifier. Let’s explain this.

Unique Product Identifiers vs Product ID

Product identifiers, like GTINs, MPNs, and others, are references that have value and purpose outside of the Google ecosystem. They are accepted on an international level as trade item numbers and are expressed in a format that follows data specification guidelines (more so with GTINs, less so with MPNs).

While many items on Google Shopping have UPIs, you can also sell products without a GTIN or MPN (there are exceptions for some categories, and you can choose not to use a UPI for others). 

Product identifiers like GTINs and MPNs are publicly available, and they serve two functions: to help customers find the exact product (product matching) and to help shopping platforms distinguish counterfeit products on their networks.

On the other hand, product IDs are used to identify your products inside a Google platform. 

At the same time, apps, data feed tools, and shopping platforms require a product ID for each item you are selling, without having IDs for each product in your inventory, the platform can’t process product data. 

The product ID attribute is used to refer to the item, and this reference is needed to configure other attributes with a supplemental feed (and many other interventions in the feed).

The product ID is not available outside of your account on a shopping platform or your product feed (although it can be shown in the URL of a product page, as part of the full address).

Let’s see how product IDs are used for tracking items that are similar, yet different.

Performance History Is Tied to Product IDs

Performance history for the specific products is tied to the product ID. This is very important for smart campaigns, but also for any analysis you may want to make on your own. If the campaign metrics aren’t connected to a specific product, you won’t be able to do a detailed analysis, rather simply note general trends.

Of course, Google’s approach to data is granular and it won’t accept a product feed entry without a valid ID attribute, so you will get comprehensive analytics per each product ID.

These are just some of the ways product IDs are used in Google Shopping. In the next section, we’ll cover the formatting guidelines for this attribute.

Options for Product ID

Google requires the value for product ID attributes to be submitted in a supported format, otherwise, the item will be disapproved.

The format for the ID attribute is up to 50 Unicode characters that should be alphanumeric. Dashes and underscores are also accepted, and they come in handy for handling different variations of the same product.

A group of products can have the same parent ID (also known as item group ID). Product variants sometimes get unique IDs by adding a dash and alphanumeric.

For instance, if the parent ID is “shopify_BE_603294072860_7397159403548”, variants can be denoted as: 

  • “shopify_BE_603294072860_7397159403548 – 1,” 
  • “shopify_BE_603294072860_7397159403548 – 2,” 
  • “shopify_BE_603294072860_7397159403548 – 3” 

The product ID is often part of the URL featuring the product page.

Next, let’s see how you can assign product IDs.

Product IDs and Product Data in Your  Feed

As we already mentioned, Google assigns product IDs, so you don’t need to add them to the feed. 

What’s more important is not to change the ID once it’s assigned to a specific product. Google uses the ID to track all of the product data, so just stick with it (otherwise, you’ll lose the performance history).

Let’s take a look at how IDs are connected to product data in the feed.

Product ID & Supplemental Feeds

Supplemental feeds are an additional data source for populating product attributes, usually used to provide values for optional attributes (though they can be used for required attributes as well). Whenever you add a supplemental feed, the product ID is used to match the additional data to a specific product in your inventory.

Without product IDs, there isn’t a way to update product data using a supplemental feed.

Product ID & Promotions Feeds

Using a promotions feed, merchants have the option to select a group of products that are available at a special promotional offer. If all products in your inventory are part of the promotion, there is no need to create an additional feed – you can apply a feed rule to all items.

However, to match products with promotions, you need a product ID. When used in a promotion, it’s known as promotion ID (roughly following the same product data specification rules). Also, it’s not recommended to change the promotion ID once you set it up because if you do so, you are practically overwriting the promotion and you’ll lose all product-related data collected up to that point.

Product ID & Dynamic Remarketing

Product IDs are crucial for another important metric, the match rate.

The match rate is the number of product views that match products from your feed, divided by the total number of product views. It’s often expressed as a percentage.

This percentage serves as an indicator of how well your feed is integrated to show dynamic product ads within remarketing campaigns. 

If the match rate is below 40%, it will negatively affect overall performance (the other metrics, like conversions). Sometimes, the match rate can be low because of issues with the retargeting pixel, however, it can also be a result of a change in product IDs.

Once you solve the mismatch between product IDs in your supplemental feed and the original product IDs, you can see performance metrics returning back to normal.

Unfortunately, this is not the only issue you can have with product IDs. Let’s check out more examples in the next section.

Common Problems With the Product ID Attribute

If you don’t comply with Google’s minimum requirements for product IDs, the products with invalid IDs won’t be served in ads. Here’s a list of recommendations to avoid this:

The product ID needs to be unique per country of sale

This applies to those merchants who sell in a multilingual country, like Belgium, Switzerland, or India. Google uses product ID, country, and language to identify a product, so when your customers use more than one language, stick to the same product ID for that country. It’s just one of the many things you need to keep in mind when you enter an alternative market abroad.

Don’t change the product ID

We’ve already mentioned this, but it’s so important and can not be overstated. Google uses the ID attribute to track each product’s history, so if you change the product ID, you will reset all the data that was collected up to that point. Even if you are still selling the same product, once you switch to a new product ID to refer to it, Google will consider it as a completely new product.

Use only supported characters in the product ID

The formatting specifications for the ID attribute are minimal, so make sure you follow them. Don’t use characters that aren’t Unicode. 

Product IDs are case sensitive

Lower and upper case can be used to differentiate between two product IDs within Google Merchant Center. However, please note that this can also cause problems with IDs in a supplemental feed or when a product is tracked by a remarketing tag (for example, Google may consider 23510-bka-583 and 23510-BKA-583 to be the same at some point of data analysis). It’s recommended to provide different alphanumerics instead of case-sensitive versions of the ID.

Use SKUs as product IDs

Feel free to use the same SKU that designates products in your in-house inventory for a product ID in your product feed. They are unique and each product has them, so you are simply repurposing them to be used in the feed.

Do note that in this case, every variant of the product needs to have a unique SKU. For example, if you sell t-shirts and use the same SKU for all colors, this won’t work as a product ID. So, have one SKU for a green t-shirt, another SKU for a yellow t-shirt, etc.

Stay On Top of Product IDs in Your Feed

The product ID attribute is required for all entries in your feed and you can’t have a successful campaign without it. Think of it as a reference that’s used whenever Google needs to process product data within and between your merchant accounts (including data feed tools).

Indeed, the product ID is used all the time: to track performance history, set up promotions, enable changes to product feed attributes through supplemental feeds, calculate match rate for remarketing campaigns, etc.

If you get a notification that your product is disapproved because of an invalid ID, the issues are usually easy to resolve because the formatting rules for this attribute are straightforward. It’s recommended to use your SKUs as product IDs, this will probably solve most of the issues with the ID attribute in your feed.

Dennis Moons

Dennis Moons is the founder and lead instructor at Store Growers.

He's a Google Ads expert with over 12 years of experience in running Google Ads campaigns.

During this time he has managed more than $5 million in ad spend and worked with clients ranging from small businesses to global brands. His goal is to provide advice that allows you to compete effectively in Google Ads.

Follow him on Twitter or LinkedIn.


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