Assemble-to-Order (ATO) translates as assembly by order. It is a production engineering approach in which products are not manufactured in stock, but on the basis of a customer order.
Assemble-to-order involves the assembly and final production of customer-specific products from prefabricated components. These can be modules, circuit boards or assemblies. Assemble-to-order is a supply chain management (SCM) strategy. Other strategies are design-to-order, known as engineer-to-order (ETO), or make-to-order (MTO) production.