Custom label template for Google Shopping

The custom label template: one job per slot

Google's own examples for custom labels are season, selling rate, price range, margin and release year. The template below turns those into five fixed slots with a closed vocabulary, so a campaign built on 'custom_label_0 = 50-99' still works next quarter. Keep values lowercase ASCII; Google compares them case-insensitively but your reports will not.

Which labels a feed rule can fill, and which it cannot

Anything that is already a column, or can be derived from one, is a rule: a price band from price, a stock label from quantity and lead time, a season from category or tag, newness from a created date. These update on every sync with no human in the loop.

Margin and performance are different. Your store export rarely carries cost, and it never carries last month's sales. (When it does carry cost, the margin band is a rule too: calc{} can divide price minus cost by price.) Those come from a second file (a cost sheet from finance, a sales export from the store or Google Ads) joined onto the catalog by SKU. In Textfinity that join is a merged source; once the sheet is joined, the margin column maps to custom_label_1 like any other attribute, and the sheet's owner refreshes it on their own schedule.

Price bands need numbers, and Textfinity's advanced expressions have them: calc{[price]} reads the first number in the price ("29.00 USD" becomes 29), and nested if/else compares it against each breakpoint. Uneven breakpoints cost nothing extra; change the numbers in the expression.

if calc{[price]} < 20 then "0-19"
else if calc{[price]} < 50 then "20-49"
else if calc{[price]} < 100 then "50-99"
else "100-plus"

Filling custom labels in Merchant Center versus in the feed

Merchant Center can also set custom labels with attribute rules ('Set to' with a condition, which needs the Advanced data source management add-on) or with a supplemental Google Sheet keyed on id. Both work, and both put the logic somewhere only one person can see. Filling the labels in the feed tool keeps every rule next to the title and filter rules, versioned with the feed, and makes the same labels available to Meta and Microsoft feeds, where the attribute is spelled the same way.

The practical split most stores land on: rule-based labels (0, 3, 4) in the feed tool; data-based labels (1, 2) from a merged sheet in the feed tool; nothing in Merchant Center except a reporting view. If you already have labels in Merchant Center rules, move them one slot at a time and check the campaign filters still match.

Custom label values that cause trouble

Four patterns waste the five slots. Free-text values ('Summer sale 2026!!') blow past the 1,000-unique-value cap once someone types variants. Values that duplicate an existing attribute (brand, product_type, google_product_category) are already available for campaign subdivision and cost a slot for nothing. Numeric bands with overlapping edges ('0-50' and '50-100') put $50 products in both or neither depending on the rule order. And labels that change meaning ('label 2 was performance, now it is color') break every campaign filter silently.

Textfinity's feed hygiene profile shows the value distribution per column, so after the first build you can see that custom_label_0 has five values and custom_label_2 has 400 before Google starts ignoring the extras.