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Products & Catalog

Prerequisite: SDK initialized and anonymous auth completed. See setup/.

Quick Reference

Task	SDK Method
List products	sdk.catalog.listProducts({ page, limit, category_id })
Get product detail	sdk.catalog.getProductDetail({ product_id_or_slug })
List variants	sdk.catalog.listProductVariants({ product_id })
Get variant detail	sdk.catalog.getVariantDetail({ product_id, variant_id })
List SKUs (flat)	sdk.catalog.listSkus()
List categories	sdk.catalog.listCategories()
Search products	sdk.catalog.searchProducts({ query: searchTerm, filter?, sort?, facets? })
Get reviews	sdk.catalog.listProductReviews({ product_id })
Submit review	sdk.catalog.createProductReview({ product_id }, { ... })
Similar products	sdk.catalog.listSimilarProducts({ product_id })
Upsell products	sdk.catalog.listUpSellProducts({ product_id })
Cross-sell products	sdk.catalog.listCrossSellProducts({ product_id })

Product Hierarchy

Understanding the Product → Variant → SKU relationship is critical:

Product (has_variant: false)
  └─ A simple product with one SKU, one price

Product (has_variant: true)
  ├─ Variant A (Color: Red, Size: M) → SKU: "RED-M-001"
  ├─ Variant B (Color: Red, Size: L) → SKU: "RED-L-001"
  └─ Variant C (Color: Blue, Size: M) → SKU: "BLU-M-001"

Concept	Return Type	Description	When to Use
Product	Product	Base item with nested variants array	PLP where one card per product is desired (e.g., "T-Shirt" card showing color/size selectors)
Variant	—	A specific option combo (Color + Size)	PDPs, cart items — accessed via listProductVariants() or nested in Product
SKU / Item	Item	Flat sellable unit — each variant is its own record	PLP where a flat grid is desired (each color/size combo = separate card), or any page with filters/sorting/search

Decision Tree

User Request
    │
    ├─ "Show products" / "Product list"
    │   ├─ With filters/sorting/search? → sdk.catalog.searchProducts({ query, filter, sort, facets })
    │   │   → Returns Item[] (flat SKUs) + facet_distribution + facet_stats
    │   ├─ Flat grid (no filters)? → sdk.catalog.listSkus()
    │   │   → Returns Item[] (flat SKUs)
    │   └─ One card per product (group variants)? → sdk.catalog.listProducts()
    │       → Returns Product[] (with nested variants)
    │
    ├─ "Product detail page"
    │   ├─ sdk.catalog.getProductDetail({ product_id_or_slug })
    │   └─ If has_variant → sdk.catalog.listProductVariants({ product_id })
    │
    ├─ "Search" / "Filter" / "Sort"
    │   └─ sdk.catalog.searchProducts({ query, filter, sort, facets })
    │       → Returns Item[] + facet_distribution + facet_stats
    │
    ├─ "Categories" / "Navigation"
    │   └─ sdk.catalog.listCategories()
    │
    ├─ "Reviews"
    │   ├─ Read → sdk.catalog.listProductReviews({ product_id })
    │   └─ Write → sdk.catalog.createProductReview({ product_id }, body)
    │
    └─ "Recommendations"
        ├─ Similar → sdk.catalog.listSimilarProducts()
        ├─ Upsell → sdk.catalog.listUpSellProducts()
        └─ Cross-sell → sdk.catalog.listCrossSellProducts()

Key Patterns

Product Listing Page (PLP)

For PLPs with filters, sorting, or search — use searchProducts (recommended). It returns Item[] (flat SKUs) plus facet_distribution and facet_stats for building filter UI:

const { data, error } = await sdk.catalog.searchProducts({
  query: "running shoes",
  filter: "pricing.selling_price 50 TO 200 AND categories.name = footwear",
  sort: ["pricing.selling_price:asc"],
  facets: ["categories.name", "product_type", "tags"],
  page: 1,
  limit: 20,
});

// data.skus → Item[] (flat list — each variant is its own record)
// data.facet_distribution → { [attribute]: { [value]: count } }
// data.facet_stats → { [attribute]: { min, max } } (e.g. price range)
// data.pagination → { page, limit, total, total_pages }

// filter also accepts arrays — conditions are AND'd:
// filter: ["product_type = physical", "rating >= 4"]
//
// Nested arrays express OR within AND:
// filter: ["pricing.selling_price 50 TO 200", ["categories.name = footwear", "categories.name = apparel"]]

For PLPs without filters where one card per product is desired (variants grouped under a single card):

const { data, error } = await sdk.catalog.listProducts({
  page: 1,
  limit: 20,
  category_id: ["cat_123"],  // Optional: filter by category
});

// data.products → Product[] (each product may contain a variants array)
// Check product.has_variant to know if options exist

For a flat grid without filters (each variant = separate card):

const { data, error } = await sdk.catalog.listSkus();
// Returns Item[] — same flat type as searchProducts

Product Detail Page (PDP)

const { data, error } = await sdk.catalog.getProductDetail({
  product_id_or_slug: "blue-running-shoes",
});

const product = data?.product;

// Prefer product.variants from getProductDetail.
// Fetch separately only if variants are missing or you specifically need the variants endpoint.
if (product?.has_variant && (!product.variants || product.variants.length === 0)) {
  const { data: variantData } = await sdk.catalog.listProductVariants({
    product_id: product.id,
  });
  // variantData.variants contains all options with pricing and stock
}

Canonical Variant URL State (PDP)

Use option query params as source of truth for variant products: ?size=large&color=blue.

• Query keys should be plain option.key values (no custom prefixes).
• Render option groups in variant_options order (do not derive option groups by iterating variants).
• Match a variant only when all option keys match variant.associated_options.
• Normalize option values consistently before comparison:
  • color → compare with option.value.name (use option.value.hexcode for swatch UI)
  • single-select → compare with option.value
• variant query param is optional derived state:
  • Set/update it when options resolve to one variant.
  • Remove it when selection is incomplete/invalid.
  • If URL has only variant, backfill option params from that variant.
  • If URL has partial options + valid variant, fill only missing options from that variant.
  • If variant is invalid, fall back to default (is_default, else first variant).
• Disable Add to Cart until required options are selected and the resolved variant is purchasable (stock_available or backorder).
• Disable option values that cannot lead to a purchasable variant under current partial selection.

Use canonical SDK types directly:

import type {
  AssociatedOption,
  Product,
  Variant,
  VariantOption,
} from "@commercengine/storefront-sdk";

Do not derive these app-level types from OpenAPI schemas.

Reference implementation:

• references/pdp-option-model.md (URL state + variant matching + attribute/variantOption UI unification)

Attribute vs VariantOption (PDP Consistency)

Treat variant_options as variant-driving attribute keys (usually single-select and color), not as a completely separate display domain.

• Non-variant products can still expose ProductAttribute values for the same keys.
• Brands may want the same UI treatment for those keys in PDP, even when product has no variants.
• Keep one normalized option-display model:
  • Variant product: selectable options from variant_options + variant.associated_options.
  • Non-variant product: read-only option-style groups from attributes for keys/types the brand wants to style as options.
• If attribute.key overlaps a variant_option.key on variant products, render the variant-option UI once and avoid duplicate attribute rows.
• Use attribute.key alignment plus attribute type (single-select/color) as primary signals.
• Cart rule stays strict: only variant products require variant resolution before Add to Cart.

Product Types

Type	Description	Key Fields
physical	Tangible goods requiring shipping	shipping, inventory
digital	Downloadable or virtual products	No shipping required
bundle	Group of products sold together	Contains sub-items

Inventory & Availability

• stock_available — Boolean, always present on Product, Variant, and SKU schemas. Use it to disable "Add to Cart" or show "Out of Stock" when false.
• backorder — Boolean, set per product in Admin. When true, the product accepts orders even when out of stock. If your business allows backorders, keep the button enabled when stock_available is false but backorder is true.
• Inventory count — Catalog APIs (listProducts, listSkus, etc.) support including inventory data in the response. Use this to display numeric stock levels in the UI.

Customer Groups & Pricing

An advanced feature for B2B storefronts where the admin has configured customer groups (e.g., retailers, stockists, distributors). When customer_group_id is sent in API requests, product listings, pricing, and promotions are returned for that specific group.

Do not pass the header per-call. Set it once via defaultHeaders in SDK config (see setup/ § "Default Headers"). After the user logs in, update the SDK instance with their group ID — all subsequent SDK calls automatically include it.

Wishlists

Commerce Engine supports wishlists (add, remove, fetch) via SDK methods. These skills cover the main storefront flows — for wishlists and other secondary features, refer to the LLM API reference or CE docs.

Common Pitfalls

Level	Issue	Solution
CRITICAL	Building PLP with filters using listProducts()	Use searchProducts({ query, filter, sort, facets }) — it returns data.skus (Item[]) + data.facet_distribution + data.facet_stats. listProducts() returns Product[] with no facets. Uses Meilisearch filter syntax (e.g. "rating > 4 AND product_type = physical").
CRITICAL	Confusing Product vs Item types	listProducts() returns Product[] (grouped, with variants array). listSkus() and searchProducts() return Item[] (flat — each variant is its own record).
CRITICAL	Using variant as PDP URL source of truth for multi-option products	Keep option params (size, color, etc.) canonical; treat variant as derived/backfill-only.
HIGH	Resolving variants from a single option or variant_options only	Match against variant.associated_options across all option keys.
HIGH	Deriving option/variant types from generated schemas in app code	Import SDK types directly from @commercengine/storefront-sdk (AssociatedOption, VariantOption, Variant, Product).
MEDIUM	Treating attributes and variant_options as unrelated PDP UIs	Build a unified option-display model so shared keys (e.g. metal) can render consistently across variant and non-variant products.
HIGH	Ignoring has_variant flag	Always check has_variant before trying to access variant data
HIGH	Adding product to cart instead of variant	When has_variant: true, must add the specific variant, not the product
MEDIUM	Not using slug for URLs	Use slug field for SEO-friendly URLs, product_id_or_slug accepts both
MEDIUM	Missing pagination	All list endpoints return pagination — use page and limit params
LOW	Re-fetching categories	Categories rarely change — cache them client-side

See Also

• setup/ - SDK initialization required first
• cart-checkout/ - Adding products to cart
• orders/ - Products in order context
• nextjs-patterns/ - SSG for product pages with generateStaticParams()

Documentation

• Catalog Guide: https://www.commercengine.io/docs/storefront/catalog
• API Reference: https://www.commercengine.io/docs/api-reference/catalog
• LLM Reference: https://llm-docs.commercengine.io/storefront/operations/list-products