Shopify knows your stock levels, but most of the storefront cannot see them. Themes, search filters, discount conditions and marketing feeds act on tags, not inventory counts. Tagging products by inventory state is the bridge: it turns a number the platform holds into a signal the rest of your stack can use.
A minimal tag set
- Tag sold-out when sellable inventory hits zero — themes can badge the card, filters can exclude it.
- Tag low-stock at a threshold you choose, and use it for urgency messaging you can actually stand behind.
- Tag restocked for a fixed window after inventory returns, to power "back in stock" sections and campaigns.
Keep names lowercase, hyphenated and boring: sold-out, low-stock, restocked. Cleverness in tag names costs you months later when a filter quietly stops matching.
The rule that makes tags useful
A tag is only worth acting on if it is always true. That means tags must be applied and removed by the same automated process, the moment inventory changes. A sold-out tag that lingers after restock is worse than no tag: it hides buyable products from filters and feeds.
Start with the three tags above, wire one theme feature and one filter to them, and expand only when something downstream needs a signal it cannot get. Tag sets grow ugly fast; inventory state is the one place they should stay small.
Inventory-state tagging, built in
Auto push down & hide sold-out products