You ship an event-driven system. Producers emit events, queues absorb them, and consumers process them. Everything looks elegant on the architecture diagram. Then traffic spikes. Suddenly, consumer services lag. Message
You usually do not discover slow database queries because someone says, “Query 42 is bad.” You discover it because checkout feels sticky, dashboards time out, worker queues back up, or
You usually discover you need rate limiting the same way you discover you need backups: something catches fire, you say “huh, that’s weird,” and then you spend the next 48
At a small scale, “too many requests” is an annoyance. At a real scale, it is an outage generator. The failure mode is sneaky: your hottest endpoint starts getting hammered
You do not really “build for peak.” You build for Tuesdays that suddenly look like Black Friday, plus the awkward half hour after a deploy when half your fleet is
You rarely notice foreign keys when they work. They sit quietly in your schema, enforcing order. They prevent orphaned records, protect invariants, and make your joins predictable. But when they’re
You do not optimize your way to millions of requests per minute. You architect your way there, then you operate your way there. At that load, the enemy is not
You ship a new feature. Traffic spikes. One downstream service slows down, then times out. Threads pile up. CPU climbs. Suddenly, your healthy service becomes part of the outage. If
You usually discover your API is not fault-tolerant at the worst possible moment. A downstream service slows down. Latency climbs. Clients start retrying. Queues fill. Autoscaling kicks in too late.