The five assignment types
When you assign a guide, you choose what it applies to:
| Type | The guide shows on… | Typical use | Plan |
|---|---|---|---|
| Product | The specific products you pick | An item that fits differently from the rest of its line | Free |
| Tag | Every product carrying a Shopify tag | Cross-cutting categories like footwear or slim-fit |
Growth |
| Collection | Every product in a collection | “Jeans”, “Dresses”, “Kids” — your existing catalog structure | Growth |
| Vendor | Every product from a vendor/brand | Multi-brand stores where each brand has its own sizing | Growth |
| Global | Every product in the store | A general fallback so no product is left without a guide | Free |
The priority order
A product can match several assignments at once. FitKit shows exactly one guide per product page, picked by specificity:
Product > Tag > Collection > Vendor > Global — the most specific match always wins. A product-level assignment beats everything; a global guide only shows when nothing more specific matches.
That's the whole rule. There are no weights to tune and no ambiguity: to override what a product currently shows, add an assignment at a higher-priority level.
Worked example — a multi-brand fashion store
Say you sell apparel and shoes from several brands. A sensible setup:
- Global → your “General apparel” guide, so every product shows something from day one.
- Vendor “Maison Lyon” → that brand's own chart, because it sizes small compared to the rest of your catalog.
- Collection “Jeans” → your Pants guide (waist, hips, inseam).
- Tag
footwear→ your Shoes EU/US/UK guide, whatever collection or brand the shoe belongs to. - Product “Oversized Hoodie 01” → its own dedicated guide, because its intentionally loose fit matches no standard chart.
Now trace one product through the rules. A pair of Maison Lyon jeans tagged slim-fit, in the “Jeans” collection:
| Matching assignment | Level | Result |
|---|---|---|
| “Jeans” collection → Pants guide | Collection | Wins — highest matching level |
| Vendor “Maison Lyon” → brand chart | Vendor | Outranked by the collection match |
| Global → General apparel guide | Global | Outranked |
If Maison Lyon jeans actually size differently, tag them (e.g. maison-lyon-bottoms) and assign the brand's pants chart to that tag — tag beats collection, so those jeans switch to the brand chart while the rest of the “Jeans” collection keeps the generic Pants guide.
Good to know
- No guide, no link. If a product matches no assignment, the “Size guide” link simply doesn't render on that page. Nothing to hide, no empty modal.
- Changes apply on save. Assignments take effect immediately — reload the product page to see the new guide.
- Free plan: product and global assignments. Tag, collection and vendor assignments are part of the Growth plan.
- Read-only access: FitKit reads your products, tags, collections and vendors to resolve assignments — it never modifies your catalog.
Next: put real numbers in your charts — see create a size guide — or head back to the docs index.
Still stuck? Email us at anadvisory.fr@gmail.com.
We read everything and reply within one business day.