How to Assess a Cloud Architect in 45 Minutes

Why 45 Minutes Is Enough

Most companies allocate four to six hours to architect interviews — panels, take-homes, and multi-round conversations. At the end of all that, they're still making hiring decisions based on incomplete, inconsistent data.

The problem isn't time. It's structure. A 45-minute structured simulation produces more reliable signal than a six-hour unstructured process, because the assessment instrument — not the interviewer — drives what's being measured.

Here is exactly how to run one.

Minute 0–5: The Briefing

Start with a tight context transfer. The candidate needs to understand three things: the current system, the failure condition, and the constraint set.

The system. Describe what's running: a live order-to-cash pipeline, an AI document processing workflow, an ERP integration layer. The candidate should understand the traffic flow and the key components before the simulation begins.

The failure condition. Identify what's breaking: traffic is spiking and the service is saturating, an upstream ERP connection is dropping and requests are being lost, an LLM endpoint is being hit with adversarial input. The candidate knows what they're fixing.

The constraints. Time limit (35 minutes of active simulation), scoring dimensions, and the expectation that they'll explain their reasoning after each major decision.

Don't answer questions about what the "right answer" is. The briefing is informational, not coaching. Five minutes is sufficient; cut it off at five regardless of whether the candidate has more questions.

Minute 5–35: The Active Simulation

This is where you learn what you need to know. The candidate works inside the running system while you observe.

What to watch in the first five minutes. How does the candidate start? Do they immediately begin adding components, or do they spend time reading the existing architecture? The best architects map the system before they change it. A candidate who starts adding components before understanding what's there is a candidate who will make premature changes in production.

Component selection tells you a lot. The simulation catalog includes real cloud services with real pricing. Does the candidate select based on fit, or do they default to whatever they're most familiar with? Do they notice the cost difference between options? An architect who automatically reaches for the most expensive compute tier without checking the load profile has a cost awareness gap.

Connection patterns reveal structural thinking. Pay attention to where new components land in the architecture. A candidate adding a message queue should connect it correctly between the producer and consumer. A candidate adding a sanitizer should place it upstream of the LLM, not downstream. Incorrect connection patterns reveal conceptual gaps that verbal interviews never surface.

Reasoning capture is mandatory. After each significant component addition, the simulation prompts the candidate to explain their decision. Read these explanations. A candidate who says "I added a DLQ to catch messages the ERP drops so we don't lose order data" understands failure handling. A candidate who says "I added a queue because queues are good for this" does not.

Watch the clock behavior. Does the candidate work steadily, or do they freeze and then rush? Panic behavior under time pressure is a reliable predictor of incident response quality. An architect who makes their worst decisions when the countdown reaches 10 seconds will do the same thing at 2am during a production incident.

Minute 35–45: The Debrief

The debrief is not an opportunity for the candidate to explain what they should have done. It's a structured conversation about what they actually did.

Lead with their decisions, not your questions. "Walk me through your first three moves" is better than "Tell me about your approach." You want them to narrate their actual reasoning, not construct a post-hoc story.

Probe the tradeoffs they mentioned. If they noted cost in their reasoning capture, ask what other option they considered and why they chose this one. If they didn't mention cost, ask how they made the selection. The quality of their tradeoff reasoning predicts how they'll handle novel situations you didn't simulate.

Ask about what they didn't do. "I notice you didn't add centralized logging. Was that a deliberate choice?" This surfaces whether an omission was intentional or a blind spot. Intentional omissions with good reasoning are fine. Omissions the candidate doesn't notice are risk signals.

What to Look for in Each Dimension

The simulation scores across six dimensions. Here's what good and bad looks like in each:

Architecture design. Green flag: components in the right logical position, correct traffic flow, appropriate patterns for the scenario. Red flag: components added without connection, orphaned services, circular dependencies.

Scalability. Green flag: load balancer or queue added before scaling the downstream, horizontal scaling considered. Red flag: scaling only the bottleneck without checking what the bottleneck feeds.

Failure handling. Green flag: dead-letter queues on external connections, retry logic considered, circuit breakers mentioned. Red flag: no DLQ on the ERP connection, no mention of what happens to failed requests.

Security. Green flag: sanitizer upstream of any LLM endpoint, WAF considered for ingress, principle of least privilege mentioned. Red flag: direct path from external input to AI model, no mention of injection risk.

Governance. Green flag: monitoring component added proactively, audit logging mentioned, access control referenced. Red flag: no monitoring on new components, no awareness of compliance implications.

Cost efficiency. Green flag: pricing compared between equivalent options, right-sized compute selection, willingness to choose a cheaper component when it meets the requirement. Red flag: premium tier selected by default without justification, no mention of cost in reasoning.

Hard Red Flags

Certain behaviors disqualify a candidate regardless of their final score:

No monitoring on any new component. An architect who adds services without observability is an architect who creates blind spots in production. This is not a junior mistake; it's a pattern-level gap.

Floating agents or services. Components added without connections that serve no architectural function suggest the candidate is filling space rather than solving the problem.

No DLQ on an external connection. If the scenario includes an ERP or third-party dependency, failing to add failure handling on that connection indicates the candidate doesn't think about what happens when the dependency goes down.

Direct ingress to an LLM. Any scenario involving AI should trigger the candidate to place a sanitizer upstream of the model. Missing this is a security red flag with serious production implications.

How Scoring Removes Interviewer Bias

At the end of the session, the scoring system has computed a six-dimension score from the actual architecture state — not from impressions, not from how articulately the candidate explained themselves. The score is the same whether two different interviewers observed the session or one did.

This allows you to compare candidates on the same scale, even if they completed the assessment weeks apart with different observers. The benchmark is the architecture, not the interviewer.

Start simulating at praxirun.com — free, no signup required.