Links to other modules - MercurJS Documentation

Modules in Mercur never reference each other directly. They connect through module links. The Catalog (Medusa’s Product module) is wired into the marketplace layer with a set of links defined in Mercur core. Once a link is defined, you retrieve related records with query.graph using the link alias.

const { data: products } = await query.graph({
  entity: "product",
  fields: ["id", "title", "sellers.*", "offers.*", "changes.*"],
})

Marketplace

Linked module	Relationship
Seller	Many-to-many allowlist (`product_seller`) that controls which stores may sell a master product. Categories carry the same via `category_seller`.
Offer	A product has many offers (`offer.product_id`, read-only). Offers are how a store sells against the master product.
Product change	A product has many change records (`product.changes`, read-only): the immutable submission and review audit trail.

Attributes

Linked module	Relationship
Product attribute	Product-scoped attributes resolve under `product.scoped_attributes` (read-only). Categories link attributes through `product_category_attribute`.

Media

Linked module	Relationship
Media	Categories and collections link their artwork through the `media_images` alias (a `MediaImage` list).

Read-only links (Offer, Product change, scoped attributes) are resolved from the field on the owning record and can’t be written through the link itself. The media_images alias is deliberately not the bare images alias. That would shadow the native Product.images relation and break product queries.