After a run, Labelizer assigns every product to a performance bucket and writes that bucket to your product feed as a custom label. You can then use that label to organize and optimize your Google Ads campaigns.
What Labelizer writes
Labelizer writes one thing: the product's bucket value into a single custom label slot in Merchant Center. It does not change your titles, prices, descriptions, or any other field in your feed.
The value written is the bucket name itself, one of:
over-index(your best performers, well above target)index(performing around target)near-index(close to target, room to grow)under-index(below target, spending more than it returns)no-index(little or no clicks and impressions, barely being shown)
So a product in the strongest bucket gets the custom label value over-index, and so on.
Choosing your custom label slot
In your project settings, under Merchant Center, you choose which custom label slot (0 to 4) Labelizer should write to. Pick a slot you are not already using for something else. The settings screen shows how many products and values each slot currently has in your recent Google Ads activity, so you can avoid overwriting a label you already rely on.
Two requirements for syncing:
Merchant Center must be connected to the project.
The connected Google account needs admin access to the Merchant Center account. Read access alone is not enough to write custom labels.
Once sync is enabled, Labelizer updates the chosen slot automatically after every run.
Checking the labels reached Merchant Center
In Merchant Center, open your products and add the custom label column for the slot you selected. You should see the bucket values (over-index, index, and so on) populated on your products. Allow some time after a run for the sync to finish and for Merchant Center to refresh.
Checking the labels are in Google Ads
Custom labels flow from Merchant Center into Google Ads with the next feed update. This can take up to 24 hours. Once available, the custom label appears as a product attribute you can filter and segment on inside your Shopping and Performance Max campaigns.
Next step
When the labels are visible in Google Ads, you are ready to build campaign segments around them. See Segment your Google Ads campaigns with Labelizer buckets.