Hard-won patterns from systems with real traffic — the failure modes and fixes you only learn in production.
It returned in 40ms on your machine. In production it takes nine seconds and fires 2,001 queries. Nobody wrote 2,001 queries — EF Core did, because your local database has five rows in it and has been lying to you since the day you cloned the repo.
"Your controller passed every code review. Then Black Friday hit, the payment API went down, and your perfect controller took the entire platform with it. Resilience isn't a feature — it's the difference between degraded and dead."
The DBA noticed the prod connection string in a public GitHub commit. By lunch you were updating LinkedIn. Configuration is the boring infrastructure that ends careers — and it's not that hard to get right. Here's the playbook for IConfiguration, secrets, environments, and rotation.
A waiter who hands the ticket to the kitchen and works the floor can serve a full dining room. A waiter who stands at the kitchen window waiting for one dish starves everyone else. Your API makes the same choice every time you turn async code back into blocking code.
The Skipper's exception handling strategy was simple: when something goes wrong, throw it overboard and hope for the best. That's why Gilligan's Island had a three-year runtime. Your production API doesn't get three seasons to figure it out.