Spree Data Model

Before writing code

Fetch live docs:

1. Fetch https://spreecommerce.org/docs/developer/core-concepts/architecture for the current model graph.
2. Fetch https://spreecommerce.org/docs/developer/core-concepts/orders for the Order/LineItem/Payment/Shipment graph and state.
3. Fetch https://spreecommerce.org/docs/developer/core-concepts/metafields for Metafield (v5+).
4. Fetch https://spreecommerce.org/docs/use-case/multi-store/model for Store and Market.
5. Inspect the live spree gem source on GitHub for current column names — Spree adds columns between minors.

Conceptual Architecture

Catalog

Pricing

Order Graph

Order
├── LineItem (one per Variant)
│   └── Adjustment[]
├── Shipment (one per StockLocation involved)
│   ├── InventoryUnit
│   ├── ShippingRate
│   └── selected ShippingRate
├── Payment[]
│   ├── PaymentSession (v5.4+, provider-agnostic envelope)
│   └── source (CreditCard, StoreCredit, etc.)
├── Adjustment[] (order-level)
├── Address (bill_address, ship_address)
└── User (optional — guest orders allowed)

Plus return-flow models: ReturnAuthorization → CustomerReturn → Reimbursement → Refund.

Inventory

• StockLocation — physical / logical warehouse
• StockItem — count of a Variant in a StockLocation
• StockMovement — append-only ledger of stock changes
• StockTransfer — moves stock between locations

Shipping

• ShippingMethod — names a way to ship (UPS Ground, Express)
• ShippingRate — computed cost option on a Shipment
• ShippingCategory — categorize products by shipping needs
• Zone / ZoneMember — countries/states a method ships to

Promotions

Promotion + PromotionRule + PromotionAction + CouponCode resulting in Adjustments.

Identity

Taxes

• TaxCategory — assignable to products (e.g., "Clothing", "Books")
• TaxRate — percentage by Zone + TaxCategory

Multi-Store / Region

Shared across stores: products, inventory, customers, shipping methods, payment gateways, Markets, admin roles. Per-store: orders, shipments, payments, refunds, store credits, gift cards, themes, blogs, pages, integrations.

Spree::Metafield (v5+)

A flexible custom-data system attached to any model. Replaces ad-hoc decorators for "I just need one extra field." Use this before adding a column.

prefixed IDs (v5.4+)

API v3 exposes prefixed IDs (prod_…, ord_…, var_…, usr_…, pay_…) — these are stable string identifiers separate from the database id. Models gain a prefixed_id method.

Polymorphic Adjustments

Adjustment belongs to an adjustable (Order, LineItem, Shipment) and a source (PromotionAction, TaxRate, manual). When sums change, run order.update_totals or use Spree::OrderUpdater (or its swappable replacement via Spree::Dependencies).

Implementation Guidance

Querying Safely in Multi-Store

# WRONG — leaks across stores
Spree::Order.complete

# RIGHT — always scope by current_store in customer-facing code
current_store.orders.complete

# Admin-side: admin sees all stores by default, but check role scoping
Spree::Order.where(store_id: current_store.id)

Reading Variants With Their Pricing

variant = Spree::Variant.find(...)
variant.price_in('USD').amount    # raw decimal
variant.price_in('USD').display_price  # formatted "$19.99"
variant.amount_in('USD')          # alias for price_in(currency).amount

For v5.3+ PriceList overrides:

price = Spree::Pricing::PriceFinder.new(variant: variant, store: store, user: user, currency: 'USD').call

(Verify the live API — pricing service objects are routinely renamed.)

Order Totals

Don't recompute totals manually. Use the order updater service:

Spree::OrderUpdater.new(order).update
# or via Dependencies
Spree::Dependencies.order_updater.call(order)

Adding Custom Data Without a Decorator

Prefer Metafield over adding columns:

product.metafields.create!(
  namespace: 'my_app',
  key: 'launch_date',
  value: '2026-06-01',
  value_type: 'string'
)
product.metafield('my_app', 'launch_date')

Verify the exact API in the live metafields doc.

Designing for the Order Graph

• One Order has many Shipments when items come from different StockLocations.
• One Shipment has many InventoryUnits — one per unit sold.
• Payments are not necessarily 1:1 with orders — split tender (store credit + card) creates multiple Payments.
• PaymentSessions (v5.4+) wrap a Payment for provider-agnostic checkout flows.

Common Pitfalls

• Modifying Order totals directly — always recompute via the updater service.
• Adding columns when a Metafield would do — Metafields don't need migrations and survive upgrades.
• Ignoring Store#default — most APIs default to it, but explicit scoping is safer.
• Adjustments on canceled lines — when a line item is removed mid-order, adjustments tied to it need explicit cleanup. Use service objects, not raw delete.
• Assuming Variant.is_master ordering — the master variant is always present; option-variant ordering follows position columns.

Always cross-check column names and relationships against the live source — the data model evolves between minor releases.