How to handle technical interview questions you don't know
You've just been asked something in the technical interview that you genuinely don't know. The room goes quiet. Your first instinct is to say "I don't know" and hope they move on — but that's not how you get hired at Virtusa, WSO2, or any software company worth joining in Sri Lanka. What you do in the next sixty seconds matters more than the correct answer.
Why interviewers ask questions you can't answer
Not every technical question is designed to have a right answer from you. Experienced interviewers at companies like 99X Technology, Calcey Technologies, and IFS are watching how you think — not just what you know.
When a senior engineer asks you about a distributed systems concept you've never implemented, they're testing:
- Whether you stay calm under pressure
- Whether you know the boundaries of your own knowledge
- Whether you can reason from first principles
- Whether you're honest about what you don't know
- Whether your thinking is systematic or scattered
Candidates who bluff get caught quickly. Candidates who freeze get screened out. The ones who get hired show structured thinking on unfamiliar ground.
The "think aloud" method
The single most effective technique is to say what you're thinking as you approach the problem — even when you're not sure where you're headed.
Start with what you do know that's adjacent to the question. If someone asks you to explain a consensus algorithm and you haven't worked with distributed systems, you might say: "I haven't implemented Raft directly, but from what I understand about distributed state, the core problem is ensuring nodes agree on a single sequence of operations. Let me reason through what properties a solution would need..."
This does three things: it signals intellectual honesty, demonstrates structured thinking, and often leads you to a more useful answer than you expected. Many Sri Lankan engineering managers will actively help you along once they see you're approaching it correctly.
"We'd rather hire someone who says 'I don't know this exactly, but here's how I'd approach figuring it out' than someone who confidently gives us a wrong answer." — A senior engineering manager at a Colombo-based product company
What to say when you have no footing at all
Sometimes you genuinely have nothing adjacent to build on. That's fine — but your response still matters.
Avoid these:
- "I don't know." (full stop, silence)
- "We didn't cover that in university."
- "Can you ask me something else?"
Say this instead:
- "That's outside what I've worked with directly. Could you tell me more about the context where it comes up? I'd like to see if I can reason toward it."
- "I'm not familiar with that specific tool. Here's how I'd approach learning it if I needed to implement it quickly on the job..."
- "I can speak to the underlying problem that technique is solving — would that be useful?"
The goal is to redirect toward something you can demonstrate, without pretending you know what you don't. A good interviewer will respect this far more than a confident bluff.
Preparing for known unknowns
Before any technical interview at a Sri Lankan firm, research the company's technology stack. If WSO2 is interviewing you, expect questions on identity servers, API gateways, and enterprise integration. If it's a fintech startup, expect queries on payment systems and possibly CBSL regulations on digital payments. If it's a defence or government contractor, expect questions about legacy integration and security protocols.
Build a preparation list with three tiers:
- Things you know well — prepare to explain them cleanly, without jargon inflation
- Things you've heard of but haven't used deeply — prepare a "here's how I'd approach it" script
- Things completely outside your experience — prepare honest acknowledgement plus curiosity
Most interviewers will tell you which tier they're listening for once you're honest about where you stand.
The follow-up that almost nobody sends
If a question stumped you, don't let it end there. A brief follow-up email sent within 24 hours — "I looked into the X question you asked and found that Y is how it works; I'd approach it by doing Z on the job" — is genuinely rare among candidates in Sri Lanka and often decisive in close calls.
It shows initiative, intellectual honesty, and enough professionalism to follow through on a gap you identified in yourself. Three years from now, when you're the one running interviews at your Colombo office, you'll remember exactly which candidates sent that email — and you'll have hired most of them.