# InventorySourceSelectionApi module The `InventorySourceSelectionApi` module provides service contracts for source selection algorithms (SSA). This module is part of the new inventory infrastructure. The [Inventory Management overview](https://devdocs.magento.com/guides/v2.3/inventory/index.html) describes the MSI (Multi-Source Inventory) project in more detail. ## Installation details This module is installed as part of Magento Open Source. It cannot be deleted or disabled. ## Extensibility The `InventorySourceSelectionApi` module contains extension points and APIs that 3rd-party developers can use to provide custom inventory source selection algorithm functionality. ### Public APIs Public APIs are defined in the `Api` and `Api/Data` directories. ### REST endpoints The `etc/webapi.xml` file defines endpoints for setting the SSA and retrieving a list of valid SSAs.