Multi-Source Inventory (MSI) project is designed to enable manage stock in multiple locations so that merchants can properly reflect their physical inventory in Magento without having to use extensions or customization.
This project is driven by Magento 2 Community developers and all results of this project will be added to Magento 2 Community Edition for free.
Code:
Wiki: https://github.com/magento-engcom/magento2/wiki