The following is from documentation provided by the Klaviyo team. For more information or questions, please contact Klaviyo's success team at success@klaviyo.com. 

Feed file size limit

Please note, the size of any one feed file should not exceed 100 MB. If it will exceed this amount, please split the feed into multiple files. For optimal performance, we recommend each feed file not
exceed 50 MB. All files used as sources will feed into the same catalog in Klaviyo. 

Sync your product catalog to Klaviyo as a custom catalog source, and then populate information from this source inside of your emails.

Their custom catalog feature can be used to populate the Product Block in Klaviyo, which supports easily inserting hand-picked catalog items in an email as well as using Klaviyo-generated product recommendations. 

Once your feed has been built and added/mapped to your Klaviyo account, you will be able to use their
Product Feed, Product Block, and Catalog Lookup Tag features. Klaviyo will refresh the information in the catalog every 6 hours. Note, your feed in GoDataFeed will only update as often as you have daily scheduled imports.

Prepare your feed in GoDataFeed

Before you proceed, ensure you have added the Klaviyo feed template, mapped and compiled products. You will need to create your feed pull URL from the feed settings page also. 

Adding or removing feed fields

If you want to add or remove fields from your Klaviyo template, then simply clone the feed template by using the options dropdown menu on the Feeds page. Cloned feeds are custom templates that allow you to modify the fields and other details of the template. 

Sync your catalog to your Klaviyo account

Once you have compiled your feed in GoDataFeed, the next step is to sync your catalog feed with your Klaviyo account.

Step 1  Add your feed to your Klaviyo account

Add your feed to your account by following these steps:

1. Navigate to the Catalog Source page on your account (note, this is not the Data Feeds page)
2. Name your feed source (ie. "GoDataFeed")
3. Copy and paste the Feed Pull URL from GoDataFeed into the Source URL in Klaviyo
   1. In GoDataFeed, go to Feeds > Klaviyo > Settings > Feed pull
   2. If you have not done so already, click "Create feed URL"
   3. Example feed URL https://api.godatafeed.com/v1/1fff91d9f56e45cbaf95ff8e89956667/feeds/K1VoeG55TjJ3VW5KVmsrZVVoR1NKUT09/download?isBypassRunningImport=true
      
      
4. SKIP the username and password
5. Click “Define Source”

Step 2  Map feed fields in Klaviyo

After your feed has been added as a catalog source, you can configure the mapping of the fields in the
feed.

1. From the Catalog Source page, click on “Configure field mapping” to the right of the feed you just added.
   
   
2. Klaviyo will try to automatically map the fields in your feed based on the field names, but if they do not automatically map you may need to set them yourself. The mapping should look like this:
   
   
   • The “Required?” column will tell us to only sync items that include that designated field.
     This is auto-populated for fields we require by default and can be optionally toggled for
     additional fields.
   • If you have extra metadata you would like to pass for catalog items, you can create a
     new field to map it to by typing the new field name into the “Klaviyo Field” section for that
     field and clicking “Create option _____”
     
     

Step 3  Finalizing your catalog

Once you’ve mapped the catalog feed in your account, the last step in the setup is to reach out to our Support Team with the following information:

1. The name of the metric on your account you would like to use for personalized recommendations.
2. The name of the event property on that metric corresponds to the unique ID ($id) used in
   your catalog feed.

Once this step is complete, you will be able to access and use the Product Feed and Product Block
features.

Getting help

Klaviyo Support Team can be reached via email or in-app Live Chat.