Why is synchronous fan-out (one request calling many services) risky, and how do you reduce it?

Answer

It increases latency (you wait for multiple calls), increases failure probability (one dependency failing breaks the whole request), and can amplify load. Reduce it by aggregating in a BFF/API Gateway, caching, using async/event-driven flows, and by setting timeouts + bulkheads so one slow dependency doesn’t stall everything.