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LetsGit.IT/Categories/Microservices
Microservicesmedium

Synchronous vs asynchronous communication — what’s the trade-off?

Tags
#communication#http#messaging#eventual-consistency
Back to categoryPractice quiz

Answer

Sync calls (HTTP/gRPC) are simpler and give immediate response, but create tight coupling and can cascade failures. Async messaging improves decoupling and resilience, but adds eventual consistency and operational complexity (queues, retries, ordering).

Advanced answer

Deep dive

Expanding on the short answer — what usually matters in practice:

  • Context (tags): communication, http, messaging, eventual-consistency
  • Scaling: what scales horizontally vs vertically, where bottlenecks appear.
  • Reliability: retries/circuit breakers/idempotency, observability (logs/metrics/traces).
  • Evolution: keep changes cheap (boundaries, contracts, tests).
  • Explain the "why", not just the "what" (intuition + consequences).
  • Trade-offs: what you gain/lose (time, memory, complexity, risk).
  • Edge cases: empty inputs, large inputs, invalid inputs, concurrency.

Examples

A tiny example (an explanation template):

// Example: discuss trade-offs for "synchronous-vs-asynchronous-communication-—-what"
function explain() {
  // Start from the core idea:
  // Sync calls (HTTP/gRPC) are simpler and give immediate response, but create tight coupling 
}

Common pitfalls

  • Too generic: no concrete trade-offs or examples.
  • Mixing average-case and worst-case (e.g., complexity).
  • Ignoring constraints: memory, concurrency, network/disk costs.

Interview follow-ups

  • When would you choose an alternative and why?
  • What production issues show up and how do you diagnose them?
  • How would you test edge cases?

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