What's Actually Behind the API Endpoint?

Most developers treat the API endpoint as a magic curtain — send a request, get a response, and everything in between is someone else's problem. But at the scale of OpenAI or Anthropic, that "in between" is a distributed system in its own right. This episode explores the tiered routing architecture behind public-facing APIs: global load balancers at the edge, Envoy proxy in the gateway layer, and internal service meshes routing to inference servers. We break down how Envoy's xDS APIs enable dynamic configuration without reloads, how circuit breaking and outlier detection prevent cascading failures, and why Stripe built a custom gateway to handle idempotency at the routing layer. If you've ever wondered what actually happens after you hit "send" on an API request, this one's for you. Episode #210413 — open it directly at myweirdprompts.com/210413