How to keep your core clean when the outside world refuses to be consistent. A Problem Every Backend Engineer Hits At some point, you build a system that needs to talk to multiple external services. Maybe it's payment providers, cloud storage buckets, notification services, or data warehouses. The business logic is the same across all of them. But every single one has a different idea of what "connecting" looks like. One wants an API key. Another wants a key and a secret. A third wants a username and password. A fourth wants a signed certificate. None of them are wrong. They just aren't consistent with each other. So the question becomes: where does all that difference live in your system? Where It Usually Goes Wrong The path of least resistance is to pass the raw config straight through and let the core figure it out. It works fine for the first integration. By the third it starts getting messy.…