Design a distributed online shopping system. Define the architecture where clients can browse products, add them to their carts, and place orders. Consider scalability, data consistency, and fault tolerance in your design.

In this design, we can use a microservices architecture where different services handle product browsing, cart management, and order processing. Use a NoSQL database for product storage for scalability and a relational database for order transactions to ensure ACID properties. Introduce message queues for async processing of orders to enhance performance and utilize load balancers to distribute requests evenly.