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Meta·Software Engineer·Onsite - System Design / Architecture·Senior

Senior
Jun 2026

Summary

Meta SWE interview with a system design question on microservices. Not much detail to go on but it's the kind of question that sounds straightforward until you're actually in the room.

Questions Asked (1)

Q1

How do microservices work? Walk through the architecture and how services communicate and coordinate.

System DesignTechnical Trade-offsAPI & Integrations
Author's notes

Pretty open-ended prompt.

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AI HintsAI Generated

Suggested Approach

Start by defining microservices as independently deployable services organized around business capabilities, then walk through the architecture from client to services to data stores. Explain communication patterns (synchronous vs asynchronous) and coordination mechanisms (service discovery, API gateway, orchestration/choreography), and finish by discussing trade-offs like complexity, latency, and consistency.

Pro tip: Anchor your answer in a concrete example (e.g., an e-commerce order flow) and explicitly contrast microservices with a monolith to show you understand when the architecture is worth its operational cost.

1. Define and motivate microservices

Briefly define microservices as small, independently deployable services owning their own data, and state why organizations adopt them: independent scaling, team autonomy, and fault isolation.

2. Describe the high-level architecture

Walk through the layers: clients, API gateway/BFF, service mesh or load balancer, individual services, and per-service databases. Mention infrastructure concerns like containers, orchestration (Kubernetes), and observability.

3. Explain communication patterns

Cover synchronous communication (REST, gRPC) for request/response and asynchronous communication (message queues, event streaming like Kafka) for decoupling and resilience. Discuss when to use each.

4. Explain coordination mechanisms

Describe service discovery (client-side vs server-side), API gateway routing, and coordination patterns: orchestration (central controller) vs choreography (event-driven). Mention sagas for distributed transactions.

5. Discuss trade-offs and challenges

Highlight challenges: network latency, partial failures, data consistency (eventual consistency), debugging complexity, and operational overhead. Explain how patterns like circuit breakers, retries, and idempotency mitigate them.

Key Points to Mention

  • Independently deployable services with bounded contexts and decentralized data management
  • API gateway as a single entry point for routing, auth, and rate limiting
  • Synchronous (REST/gRPC) vs asynchronous (message queues/events) communication and their trade-offs
  • Service discovery and load balancing for dynamic scaling
  • Saga pattern and eventual consistency for distributed transactions
  • Resilience patterns: circuit breakers, retries with backoff, idempotency, and observability

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.