Most APIs return 200 OK. That’s usually treated as completion. In many systems, it isn’t. It’s only the boundary. It only means the request crossed the API boundary successfully. After that, the real execution starts. queues workers routing decisions provider behavior delivery state retries This is where most production issues live. Not before the response. After it. The problem with treating 200 OK as the result A synchronous API response looks simple: client → API → 200 OK It feels complete. But in many systems, the API response only confirms that the request was accepted. Not that the work finished. accepted ≠ executed executed ≠ delivered Collapsing these into one “success” makes systems hard to reason about. Before 200 OK Before the API returns success, several things happen: authentication defines execution context validation checks request shape authorization decides if execution is allowed pricing is resolved balance or quota is checked This part is synchronous. The client is still waiting.…