Choose the most effective clarifying questions for 5 real technical interview scenarios.
The clarifying question framework
Scale: "How many users / requests per second are we designing for?"
Constraints: "Are there any time or space complexity requirements?"
Edge cases: "What should happen if the input is empty or null?"
Assumptions: "I'm going to assume [X] — is that correct?"
0 / 5 completed
1 / 5
The interviewer asks you to design a notification system. Before starting, which set of clarifying questions is most useful?
Why C is the model clarification: scope, scale, guarantees, delivery mode
System design questions intentionally leave requirements open. Great engineers clarify before designing. The four dimensions of C:
Scope: which channels — email, push, SMS — defines system complexity
Scale: DAU and volume — determines architecture choices (queue vs. direct call)
Guarantees: delivery semantics — exactly-once vs. at-least-once changes the design significantly
Delivery mode: real-time vs. batch — determines latency requirements
Why A and B fail: A asks for a feature detail (notification types) without understanding the architecture. B (tech stack) is the wrong question to lead with — stack follows requirements.
System design clarification vocabulary:
"What's the expected scale — DAU and QPS?"
"Should I optimise for consistency or availability?"
"What are the latency requirements?"
"What's in scope for today's design?"
2 / 5
A coding problem asks you to find the "largest" element in a list. This is ambiguous. How do you clarify?
Why B is the professional clarification: identify ambiguity explicitly
Noticing and surfacing ambiguity is a senior engineering skill. This answer:
Identifies the ambiguity: "numerically largest" vs. some other criteria
Gives a concrete example: "string length if the list contains strings"
Asks about an edge case: "can the list be empty" — and requests the expected output
Why A can be wrong: if the list contains objects and "largest" means by a specific field, coding for numerical max gives the wrong solution. The interviewer wants to see you surface ambiguity, not guess.
Ambiguity clarification vocabulary:
"Just to confirm — by [term] do you mean [interpretation A] or [interpretation B]?"
"I want to make sure I understand: [restate the problem in your own words]."
"What should happen in the edge case where [condition]?"
3 / 5
An interviewer asks: "Design Twitter." This is intentionally vague. What is the best first response?
Why B is the professional approach: scope before depth
"Design Twitter" (or any FAANG-scale system) is intentionally open-ended. The right move:
Acknowledge the scope problem: "Twitter is a very large system"
Ask to narrow scope: propose specific feature areas to choose from
Ask about scale: full Twitter vs. simplified version
Why this matters: designing the entire Twitter in 45 minutes is impossible. The interviewer expects you to identify this and scope down. Jumping into a full architecture without scoping is a red flag — it suggests you don't ask requirements questions in real work.
Scoping vocabulary:
"To make the best use of our time, which aspect should I focus on?"
"Should I assume we're designing for [scale A] or [scale B]?"
"Is there a specific component you'd like to go deep on?"
"Let me start with a high-level design and then we can deep-dive on whichever part is most interesting."
4 / 5
The interviewer gives you a behavioural question: "Tell me about a conflict with a teammate." You want to make sure you answer the right aspect. What clarifying question (if any) is appropriate?
Why C is the professional approach: ask for specificity, then commit
For behavioural questions, a brief clarifying question is acceptable and often shows maturity:
Offers both types: "technical conflict or process conflict" — shows you understand the distinction
States your intent: "I want to share the most relevant one" — not stalling, just preparing a targeted answer
vs. B: B uses "interpersonal conflict" which has a negative connotation. "Process/communication conflict" is more neutral and professional.
vs. A: answering without clarification risks telling a conflict story that doesn't address what the interviewer is assessing. Engineers who ask good requirements questions in code interviews should do the same for behavioural questions.
Behavioural interview vocabulary:
"Can I ask whether you're looking for [X] or [Y]?"
"I have a couple of examples — one about [A] and one about [B]. Which is more relevant?"
"Let me make sure I give you the most useful example for what you're assessing."
5 / 5
You've been given a coding problem and you're not sure whether to use recursion or iteration. Neither was specified. How do you surface this assumption professionally?
Why C is the model answer: state your assumption + reasoning + invite correction
This response demonstrates senior engineering thinking:
States the assumption explicitly: "iterative solution is acceptable"
Gives technical reasoning: "recursion could hit stack limits, iteration has better space"
Stays open: "happy to switch" — not defensive about the choice
Confirms with the interviewer: "Does iterative work for you?"
vs. B: B asks a closed question that forces the interviewer to choose without knowing why you're asking. C is better because it shows you've already reasoned through the trade-offs.
Assumption-stating vocabulary:
"I'm going to assume [X] because [reason] — does that work?"
"My assumption here is [X]. If that's wrong, let me know and I'll adjust."
"I'll make this assumption explicit: [X]. I can revisit if needed."