In this help center, you can find content for both Merchant Center Next and the classic Merchant Center experience. Look for the logo at the top of each article to make sure you're using the article for the Merchant Center version that applies to you. 

ID [id] (Collections)

A custom icon for Merchant Center Classic Article Header.

Use the ID [id] attribute to uniquely identify each of your collections.

When to use

Required Required for each collection.


Follow these formatting guidelines to make sure Google understands the data you're submitting.

For details on when and how to submit values in English, learn more about submitting your product data.

Type Unicode characters (Recommended: ASCII only): alphanumeric, underscores, and dashes
Limits 1-50 characters
Repeated field No
File format Example value
Text feeds Budget_Sofas_Q1_2020
XML feeds ​<g:id>Budget_Sofas_Q1_2020<g:id>


Follow these guidelines to make sure you submit high-quality data for your collections.

Minimum requirements

These are the requirements you need to meet to show your collection. If you don't follow these requirements, we'll disapprove your collection and let you know in the Diagnostics page of your Merchant Center account.

  • Use a unique ID for each different collection. The ID allows you and Google to distinguish each collection. Remember that the ID [id] is unique to your collection and is different from the ID [id] used for products in your product feeds.
  • Use a stable ID for each collection. Once you've assigned an ID [id] to a collection, don't change it. The ID you choose identifies the collection and helps us to retrieve any associated collection-specific information. It is also used to track the associated collection's performance history in Merchant Center and Google Ads. If you change the ID, you'll overwrite your associated collection and its history.
  • Don't use casing to make IDs unique. While collection IDs are case-sensitive in Merchant Center, there may be cases in which two collections with IDs that differ only by casing are interpreted as the same collection. For example, if you submit ID "abc123" for one collection and ID "ABC123" for another, these offers may be confused in Google Ads filtering or there could be issues matching them across supplemental and primary feeds. Instead of casing, use unique combinations of letters and numbers to differentiate collections.
  • Don't reuse or recycle the same ID for different collections. For example:
    • Don't reuse an ID for different collections in the same country of sale or language.
    • Don't recycle an ID for new collections.
  • Avoid white space. Consecutive white spaces and white spaces before and after the ID will be automatically removed.
  • Don't submit invalid unicode characters. These characters are generally added during your file's encoding process. To avoid them, use UTF-8 encoding. To help prevent encoding issues, submit files in a compressed format. Examples of invalid unicode characters include:
    • Control characters (for example, U+200D)
    • Function characters
    • Private area characters
    • Surrogate pairs
    • Unassigned code points

Best practices

These best practices can help you go beyond the basic requirements to optimize your collection data for performance.

  • Use a meaningful string as the ID [id] for your collection. We will use the ID to identify your collection in various places so it is best to use a well-chosen name that describes the collection.


Sofa collection

Product data for a sofa collection
Attribute Value
ID [id] Budget Sofas Q1 2020

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