Sidecar proxies decouple infrastructure concerns from business logic by intercepting traffic at the container boundary without modifying the application source code. What We're Building We are focusing on the sidecar proxy pattern specifically. This involves understanding how a proxy shares a network namespace with a service and intercepts TCP traffic before it reaches the application. The scope is the data plane, not the control plane orchestration. We will demonstrate how a proxy sits alongside a container to handle routing, encryption, and observability. This pattern is essential for modern distributed systems where business teams do not want to maintain infrastructure logic inside their core repositories. Step 1 — Container Networking Co-location The sidecar must live in the same network namespace to share the same IP address. In Kubernetes, this is often managed via hostNetwork or explicit sidecar containers.…