Mini-Capstone - The Front Door, Assembled

Nine patterns, one boundary. This capstone designs the complete public API layer for the store: web app, mobile apps, and 200 partner integrations: by doing the one thing that makes the module cohere: walking a single request inward, from the visitor's phone in Sydney to the service that answers it, deciding at each layer what happens there and why there.

Two rules travel with us, from the module intro: everything here is one proxy primitive wearing uniforms, and the cheapest request is the one handled earliest