# Collections

A collection is a flat, ordered group of products.
Use it for a campaign, seasonal edit, gift guide, or a selection such as Desk refresh.
A product can belong to several collections while keeping the same categories and variants.

## Curate membership explicitly

Create a collection, assign products through their update inputs, and set the order you want buyers to see.
Treat membership as maintained data.
If your integration selects New arrivals by date, the integration must keep that selection current; the collection name does not create a rule.

Keep collection IDs stable across label changes.
Use a stable slug for a storefront URL, and arrange redirects if that URL changes.

## Keep presentation and purchasing separate

A collection describes a group, not permission to sell its members.
Its products still resolve in the shopper's store, publication, price, and inventory context.
Use the same context when loading a collection page and adding one of its variants to a cart.

For a Desk refresh campaign, add a lamp and desk organizer, then place the featured product first.
When the campaign ends, remove or replace the collection membership without recreating the products.

Use [categories](/concepts/catalog/categories) when a parent-child hierarchy is the important relationship.
Follow [Organize a catalog](/guides/catalog/organize-catalog) for creation, assignment, and verification.