Top 11 Technical debt Interview Questions
Browse 11 real-world technical and behavioral interview questions about Technical debt. Review scenarios, edge cases, and architectural best practices.
Make the case to a CFO for funding a modernisation programme that nobody outside engineering can see.
A modernisation business case for a CFO turns technical debt into what finance already manages: run cost, risk exposure and speed of change. Price the status quo from stated assumptions, offer options with costs, fund in gated tranches with measures, and let finance decide how the spend is treated.
You have two weeks for technical due diligence on an acquisition target. What do you look at, and what would make you tell the deal team to walk away?
Technical due diligence tests the deal thesis, not code quality. Check whether the product can do what the buyer is paying for, who holds the knowledge, which security, licence and debt liabilities come with it, and what integration costs. Turn every finding into a price, condition, plan or walk-away.
You inherit three competing rewrite proposals. How do you choose one, and how do you tell the other two teams no?
Set decision criteria tied to business outcomes before scoring anything: the measured cost of the status quo, what each rewrite changes for customers, reversibility, capacity and any incremental route. Fund one rewrite properly rather than three partially, and tell the other teams first, in person, with the reasoning.
How do you decide how much of your team's capacity goes to roadmap work rather than keeping the lights on and paying down debt?
Measure where the time is going before setting any split, publish the allocation as a policy with a rationale rather than a percentage you invented, route interrupts through one named person, and justify debt work by the delivery cost it removes instead of asking for a refactoring sprint.
You need a steering committee to fund a quarter of platform hardening instead of two customer features. How do you put technical risk and feature risk side by side so an executive can choose?
Express both in the same currency, which is expected cost to the business over a stated horizon, and show the arithmetic from assumptions the room can argue with. Give the committee a real choice with a decision date rather than a single option and a plea.
A prototype you built to prove a point is now being used as if it were production. Do you harden it or replace it?
Decide on the prototype's foundations rather than its polish: if the data model and the correctness boundaries are sound, hardening is cheaper and keeps the users you have, and if they are not, no amount of testing and monitoring will make it safe to keep.
The platform migration has no user-visible benefit. How do you rank it against features customers are asking for?
Convert the migration into the units the roadmap already uses by pricing its carrying cost and the cost of delaying it, then rank it on the same scale as features rather than arguing for it as a special category that deserves exemption. Use this prioritisation answer to show the decision, trade-off, and evidence rather than a memorised definition.
You want to reverse a decision recorded in an ADR two years ago, and everyone who made it has left. How do you go about it?
Reconstruct the original context first and test whether it has genuinely changed or whether you simply inherited a cost you dislike, then write a new record that supersedes rather than edits the old one, price the half-reversed state explicitly, and get agreement from the teams who now carry the consequences.
Feature delivery and paying down architectural debt are competing for the same engineers. How do you decide the split and defend it?
Stop treating debt as a backlog of tasks and express it as a rate — the interest you are paying in change lead time, incident load and onboarding cost — then fund only the remediation that measurably moves one of those numbers. A fixed percentage tax is easy to agree and the first thing cut under pressure.
Your team wants to rewrite a service that works. How do you decide, and how do you say no if that is the answer?
Make the team convert the ask into a measured cost the current service imposes and a payback period, then test whether an incremental route reaches the same place. Say no on the arithmetic rather than on authority, and if you say yes, agree in advance what would make you stop.
What is the Definition of Done, who owns it, and what do you do with an item that misses it at the end of a Sprint?
The Definition of Done is one shared quality standard every increment must meet, owned by the Scrum Team unless the organisation mandates a stricter minimum. An item that misses it is not partially done: it returns to the Product Backlog rather than being released or presented as complete.