The US Marketplaces Bundle connects a single Magento 2 (Open Source or Adobe Commerce) catalog to the three largest US marketplaces — Amazon (SP-API), eBay (Sell API) and Walmart Marketplace API — through one coherent set of modules installed under app/code/Ecosire/ on your own store. It is not an instant Adobe Commerce Marketplace download: ECOSIRE builds it to fit your catalog structure, attribute set and warehouse setup, then installs and supports it on your environment.

The core problem it solves is overselling across channels. A shared inventory pool reads salable quantity from Magento's Multi-Source Inventory (MSI) via the getProductSalableQty service contract and pushes a single authoritative figure to all three marketplaces, so a unit sold on eBay decrements availability on Amazon and Walmart within the same sync cycle. Sync runs on Magento cron through queue consumers, with retry and backoff so marketplace rate limits never silently drop updates.

Each channel keeps its own rules. Per-channel listing & pricing lets you map Magento attributes to Amazon listing feeds, eBay item specifics and Walmart spec fields, apply channel price markups or floors, and control which website/store-view supplies titles and descriptions. Unified order import pulls marketplace orders back into native sales_order records — with marketplace fees, buyer-shipping and channel reference stored as order attributes — so fulfillment, invoicing and credit memos run through your existing Magento workflow.

Everything respects Magento conventions: dependency injection via di.xml, plugins/observers instead of core rewrites, admin ACL for each marketplace config, REST/GraphQL endpoints for status, and structured logging. You get a maintainable extension your developers can read — not a black box. ECOSIRE delivers, installs, and supports it, with a clear lead time agreed up front.