Explain Your System Architecture

Q: Explain Your System Architecture

This question evaluates system architecture and distributed-systems competencies, including scalability, reliability, data modeling, event-driven messaging, observability, and capacity planning within the System Design domain.

Q: How do I approach System Design interview questions?

System Design questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master system design interviews.

Question

System Design Interview: End-to-End Architecture Deep Dive

Task

Explain the end-to-end architecture of a production system you built or can credibly design. Use a concrete example (e.g., real-time personalized feed, event ingestion pipeline, payments, notifications). Cover the full request and data lifecycle: clients, APIs, services, storage, async infrastructure, and observability.

For Each Module, Discuss

Purpose and responsibilities.
How to speed up the service (latency, throughput, resource efficiency).
Expected QPS/EPS with back-of-the-envelope estimates and assumptions.
Data model, partitioning/sharding, and cache strategy.
Failure modes, backpressure, and fallback behavior.
If Kafka (or a similar log) is involved:
- Producer, broker, and consumer configuration.
- Delivery guarantees (at-most-once, at-least-once, exactly-once) and how they are achieved.
- Idempotency, retries, reprocessing, DLQs, and schema evolution.

Constraints to State

Latency SLOs (e.g., p95 100 ms for reads; p99 for critical paths).
Traffic assumptions (DAU/MAU, sessions/day, requests/session, peak factor).
Data retention and compliance needs.

Deliverables

High-level architecture diagram (describe in words if you can’t draw).
Module-by-module walkthrough with the points above.
Capacity planning math (QPS, partitions, cache sizes) and key configuration choices.