Quick answer
In KitForge FBT, add-on products appear as selectable recommendations on the trigger product page. Shoppers choose which add-ons to include; the bundle discount applies to selected add-ons (and sometimes the trigger) when added via the widget path.
- Add-ons are optional FBT complements on trigger PDPs.
- Discount applies when shoppers select add-ons via widget.
- Different from fixed kit components which are always included.
- hideUnavailableAddons keeps OOS add-ons off the widget.
Why add-ons are optional by design
FBT models real attach behavior — some shoppers want the hero only. Forcing components like a fixed kit would reduce conversion on the primary SKU. KitForge applies bundle discount only when add-ons are selected and added through the widget.
Curating add-on catalogs
3–5 relevant add-ons outperform long lists. Match accessory type to trigger — same scent family for candles, compatible fit for fashion, refill logic for consumables.
FBT discount not applying unless add-on is selected is expected behavior — not a bug.
Final recommendation
Add-on products are the selectable half of FBT — curate few relevant items, verify discount on selection, and distinguish them from fixed kit components.
If you want this kind of offer to feel native to the buying journey, Kitforge Bundles is built around that exact problem: turning related Shopify products into clearer bundle offers before the shopper reaches checkout.
FAQ
Can add-ons include the trigger product?
Typically no — add-ons complement the trigger. Duplicate SKUs confuse shoppers; use quantity breaks on the trigger for multi-unit instead.
What if all add-ons are out of stock?
With hideUnavailableAddons enabled, the FBT widget may show no add-ons or hide entirely depending on configuration. Restock or swap add-ons.