AI System Design Interview Basics

AI system design interviews test whether you can connect model behavior to product outcomes, architecture constraints, and operational risk.

Clarify First

Before drawing architecture, ask about:

User and workflow.
Success metrics.
Data sources and permissions.
Latency and cost constraints.
Failure tolerance.
Safety, privacy, and compliance boundaries.

Reference Architecture

flowchart TD
  UI[Client] --> API[Backend API]
  API --> Auth[Auth + Policy]
  Auth --> Orchestrator[AI Orchestrator]
  Orchestrator --> Retrieval[Retrieval]
  Orchestrator --> Tools[Tools]
  Retrieval --> Model[Model]
  Tools --> Model
  Model --> Eval[Validation + Eval]
  Eval --> UI

Tradeoff Language

Strong candidates explain tradeoffs directly.

Decision	Tradeoff
Larger model	Better capability, more cost and latency
More retrieved context	Better coverage, higher context cost
Human approval	More safety, slower workflow
Fine-tuning	Better behavior, more data and release complexity

Evaluation Plan

For a RAG product, evaluate retrieval quality, answer correctness, citation quality, latency, cost, and user feedback. For agents, add tool-call correctness and action safety.

Common Mistake

Do not design a fully autonomous system when the user asked for a reliable assistant. Bounded workflows are often stronger and easier to ship.

Next Step

Take the AI System Design quiz, then practice explaining a document Q&A system in five minutes.