What are custom labels used for?

Custom labels are extra grouping fields (custom_label_0 to custom_label_4) that ad platforms use to segment products for bidding and reporting. Filling them by rule lets you bid differently on clearance, seasonal, or high-margin groups.

If a product is in two sets, which label wins?

The first matching case in your rule wins. Order your cases from most specific to least specific so the right label takes precedence, for example clearance before a general sale.

Can the same set drive both a label and a badge?

Yes, and that is the point. Define "Clearance" once, use it as a custom_label case and as the targeting for a clearance badge template. The two stay in sync because they read the same rule.

Do overlay-targeted templates apply to every channel?

Badged images are served only to channels that allow overlays (Meta, TikTok, Snapchat, Pinterest). Google Shopping and Microsoft always receive the clean original image, so a promo overlay never triggers a disapproval.

Custom labels and overlays by rule

Use product sets to drive two powerful outputs: custom labels in your export (great for ad campaign segmentation) and which products receive an image overlay. One rule, reused for both labeling and creative targeting.

One set, many uses

A product set is more than a filter. The same saved rule can power custom labels written into your output feed and can decide which products get a badged or framed image.

This keeps your logic in one place. Define "Clearance" once, then use it to tag products with a custom_label value for ad bidding and to target a clearance badge on the image, all from the same set.

Custom labels by rule

Channels like Google Shopping and Meta support custom labels (custom_label_0 through custom_label_4) that you use to group products for bidding and reporting. MartechFlow can fill these by rule using your product sets.

Under the hood, a custom label is set with a case rule: the first set whose rule matches a product supplies that product's label value, with an optional fallback. So a single column can read "CLEARANCE" for products in your clearance set, "SALE" for products in your sale set, and a default for everything else.

Pick the output column to fill (for example custom_label_0).
Add cases in priority order: when in the "Clearance" set, value is CLEARANCE; when in the "Sale" set, value is SALE.
Set an optional else value for products that match no case.
The first matching case wins, so order your cases from most specific to most general.

Targeting image overlays with a set

When you build an image template, its "Applies to" rule decides which products it renders on. That rule can reference a saved product set, so a template targets exactly the group you already defined.

For example, target a "Free shipping" frame only at products in your "Premium brands" set, or a clearance banner only at products in "Clearance (40%+ off)". Because templates are matched per product by priority, you can layer several set-targeted templates and let the highest-priority match win for each product.

Set it up

The workflow is the same in both cases: define the set first, then point the label rule or the template targeting at it.

1Create the product sets you want to act on (see Create product sets with rules).
2For labels: open the feed's output customization, choose the custom label column, and add a case for each set with its label value.
3For overlays: open the Creative studio, edit or create a template, and set "Applies to" to a rule referencing your set.
4Save. Label rules rebuild the export; overlay targeting takes effect on the next image render.

Good to know

Custom-label rules are evaluated per product as the export is built, so the labels reflect each product's current data on every run.

Supplemental lookup conditions (rules that read from an uploaded lookup file) work in product sets and export filters, but they are not available inside custom-label case rules. Keep label rules based on product fields and set membership.