Technical practice
How would you turn an enterprise SaaS architecture into a delivery roadmap?
What to coverSuggested preparation: Outline domain boundaries, service ownership and the order in which core capabilities would be delivered. Explain how you would balance a workable first release against scalability and integration needs.
How would you design a production Python API that performs concurrent work?
What to coverSuggested preparation: Discuss asynchronous programming in FastAPI or an equivalent framework, including where blocking work belongs and how you would control concurrency. Explain how you would test performance and diagnose a slow endpoint.
How would you design and migrate data across PostgreSQL and MongoDB?
What to coverSuggested preparation: Explain how access patterns and consistency needs inform data models and database choice. Cover query optimisation and a large-scale migration approach that limits disruption and verifies data correctness.
How would you build an LLM integration layer that can evolve across providers?
What to coverSuggested preparation: Address provider abstraction, prompt versioning, caching, fallbacks and cost control, all named in the role. Discuss the trade-offs between response quality, latency, reliability and spend.
How would you make an agentic workflow reliable when it uses external tools?
What to coverSuggested preparation: Describe orchestration, tool selection, structured-output validation and guardrails around failed or unexpected tool responses. Explain how you would bound retries and evaluate whether the workflow completes its intended task.
How would you evaluate a production RAG or semantic-search system?
What to coverSuggested preparation: Walk through retrieval and answer-quality checks, including how you would investigate poor results. Compare relevant trade-offs in indexing, freshness and latency without assuming a particular vector database.
How would you enforce tenant isolation in a multi-tenant AI SaaS platform?
What to coverSuggested preparation: Cover tenant-aware data access, RBAC, tenant-specific configuration and auditing. Explain how you would test isolation across APIs, background work and AI integrations, and what evidence would support compliance readiness.
How would you integrate enterprise systems using events, workers and webhooks?
What to coverSuggested preparation: Describe when to use an API call versus a message bus or asynchronous worker, and how you would handle retries and duplicate events. Include how third-party failures and webhook delivery would affect the integration design.
How would you design APIs and data models shared by multiple teams?
What to coverSuggested preparation: Discuss clear contracts, versioning, documentation and compatibility during change. Explain how design reviews would expose domain-boundary and integration trade-offs before implementation.
How would you deploy and observe critical backend services?
What to coverSuggested preparation: Relate Docker, Kubernetes and AWS or Azure to deployment and recovery choices, without assuming a particular cloud setup. Discuss what you would instrument with the listed observability stack and how findings would guide troubleshooting.
Behavioural practice
Tell me about a time you converted a broad architecture into an achievable delivery plan.
What to coverSuggested preparation: Give the situation, your decisions about priorities and domain boundaries, and how you aligned the team. Describe the delivery result and what you changed when constraints emerged.
Tell me about a time you led backend engineers through a difficult design decision.
What to coverSuggested preparation: Describe the situation, competing proposals and how you ran the review or resolved disagreement. State what the team implemented and the result, including any trade-off you would revisit.
Tell me about a time you mentored an engineer while maintaining delivery momentum.
What to coverSuggested preparation: Identify the situation, the support or feedback you provided, and how you balanced coaching with project needs. Give an observable result without claiming credit for someone else's work.
Tell me about a time you improved engineering standards across a team.
What to coverSuggested preparation: Use a real situation involving testing, CI/CD, code reviews or documentation. Explain the actions you took to secure adoption and the resulting change in delivery or code quality.
Tell me about a time you stayed hands-on with a critical component while leading a team.
What to coverSuggested preparation: Describe why that component needed your direct involvement, what you built or debugged, and how you avoided becoming a bottleneck. Give the result and explain how you handed off knowledge or ownership.