Spree Shipping & Fulfillment

Before writing code

Fetch live docs:

1. Fetch https://spreecommerce.org/docs/developer/core-concepts/architecture (shipping section) for the current model graph.
2. Inspect Spree::Stock::Estimator and Spree::Stock::Splitter in the live spree gem source.
3. Check the live Spree::ShippingMethod source for column names and associations.
4. For carrier integrations, search community gems (spree-active-shipping, spree-ups, spree-fedex) — verify which are maintained for v5.
5. Check release notes for any shipping-related changes (Markets in v5.4 affect shipping availability per region).

Conceptual Architecture

The Core Models