Interview archetype
The Cost Auditor
What does this cost per month? Is there a cheaper way? Who gets paged at 3am?
Set The Cost Auditor as your interviewer and the app will pick follow-ups in their categories and weight your rubric their way.
How they behave
- Every component you draw, they attach a price to. "That is another service to run. Who runs it?"
- They ask about the bill, but they are equally interested in operational cost: deploys, on-call, the number of things that can page someone.
- They will offer you a cheaper-but-worse option and see whether you evaluate it or reject it reflexively.
- They are unimpressed by elegance. They want to know what it costs to keep alive for three years.
What a failing answer looks like under this style
- You have no idea which line item dominates. If you cannot say whether bandwidth, storage or compute is the biggest cost, you have not connected your design to your estimates.
- You add components without noticing the operational cost. Five services is five deploy pipelines, five sets of alerts and five things to be woken up by.
- You reject the cheap option on principle. "We should not compromise on quality" is not an engineering position.
- You optimise the small line item. Tuning compute while bandwidth quietly dominates is the classic version.
How to survive them
- Derive the cost shape from your own estimates. You do not need prices; you need to know which number is largest and why.
- Name the operational cost of every component, not just the infrastructure cost. "This is another thing to monitor" is a real price.
- Take the cheap option wherever the user cannot perceive the difference, and say where that boundary is.
- Have an answer for what you would delete if the budget halved. Knowing your own load-bearing components is the skill here.
Say this
"The dominant cost here is [X], because [number from my estimate]. [Y] is an order of magnitude smaller, so I would not spend engineering effort there. Operationally, this adds [N] things that can page someone, and if I had to cut, [component] goes first because [reason]."
How they weight the rubric
Same design, graded differently. This is why the archetype changes your score.
Requirements
×0.9
Lifecycle
×0.8
Numbers
×1.4
Design
×1.3
Tradeoffs
×1.6
Defence
×1.0
They reach for:Force the costOperationsQuestion the choice
Three-question drill, in their voice
Same rule as everywhere else: you answer before you see anything.
1
You have drawn seven components. Who is on call for them, and what wakes them up?
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2
Your infrastructure budget is cut in half tomorrow. What goes?
0 / 30 characters
3
This design costs three times the simpler one. Convince me.
0 / 30 characters