A Senior Engineer Design Review Interview You Can Adapt

A senior engineer design review interview asks a candidate to examine a supplied technical proposal, rank the changes it needs, and explain a workable next step. Give every candidate the same requirements and assess their reasoning against stated criteria. The useful evidence is how they connect a decision to its consequences.

This format fits a particular responsibility: reviewing another engineer’s proposal before the team commits to it. It gives you a concrete proposal to discuss without asking a candidate to invent an entire system or bring confidential documents from a former employer.

Michael Lynch’s guide to writing an effective software design document drew a fresh Hacker News discussion this week. His June 2026 article argues that design documents should concentrate attention on consequential decisions, with effort proportionate to the work. That suggests a useful interview question: can this person tell which decisions deserve attention first?

The exercise below is an original, fictional example you can adapt. Its timings, facts, and scoring guide are editorial suggestions, not a validated hiring test. It makes no claim about predictive accuracy or hiring outcomes.

Start with the design responsibility you are hiring for

Use a design review when reviewing proposals is part of the actual job. A senior title alone does not tell you whether the person needs to assess access controls, data pipelines, frontend interactions, or infrastructure changes.

Write one sentence with the hiring manager: “This engineer will review proposed changes to our customer-facing backend and help the team decide what can ship.” Then identify the decisions they must handle on arrival and the context you expect to teach.

The US Office of Personnel Management’s job analysis guidance connects selection decisions to actual tasks and the competencies those tasks require. Apply that principle narrowly. If your role is mostly frontend product work, a backend export exercise needs replacing, even if your interviewers enjoy discussing queues.

Likewise, OPM’s work-sample guidance says the tested competencies should be ones applicants are expected to possess on entry. Avoid making knowledge of an internal convention the hidden pass condition when you plan to teach that convention after hiring.

Turn the responsibility into observable criteria before you invite anyone. Our guide to building ideal candidate profiles can help with that step. Keep the exercise focused: a reviewer should be able to explain which part of the advertised role each criterion addresses.

Give candidates a complete review packet

Supply the context that makes a reasoned answer possible. The packet should contain the goal, operating constraints, proposed approach, requested response, and conditions under which candidates will work.

For a first pilot, you could suggest 30 minutes of preparation and a 30-minute conversation. Those are starting points to test with colleagues, not measured completion times. If the packet cannot be reviewed within the advertised effort, shorten it before using it with candidates.

Tell candidates they can submit brief notes and that you will not grade slide design, prose polish, or the number of comments. Offer an accessible text version. Explain how to request an adjustment to the format or timing, and give a contact for questions.

State your rules for documentation, web search, AI assistance, and collaboration. If a particular tool is required, provide access. A discussion can reveal additional reasoning; it does not establish authorship or make an exercise immune to outside help.

Use synthetic data and a fictional proposal. Do not ask candidates for their previous employer’s internal designs or use the exercise to obtain a solution to your current production backlog. For the surrounding effort, compensation, and communication decisions, see how to structure code assignments.

Try this fictional customer-export proposal

Ask the candidate to review a bounded proposal rather than design an export platform from scratch. Everything in this section belongs in the candidate packet, including the constraints that make different answers reasonable.

The supplied context

Your fictional company runs a business application. Each customer organization has its own records. Authorized customer administrators want to export their organization’s records to a CSV file, a text format they can open in a spreadsheet.

The first release has these requirements and constraints:

• An administrator can request an export of records belonging to their organization.
• The file contains private customer information. Being logged in is not enough to authorize access to every organization’s data.
• The largest current customer has 200,000 records. You have not measured export generation time or peak memory use.
• Customers can accept a delay of up to ten minutes before the file is ready. They do not need scheduled exports in the first release.
• The application already has background workers and private file storage.
• Two engineers have one week for the first release. They can reduce the initial scope if they explain the customer impact.
• The team has not agreed on file retention or what happens when an administrator loses access after requesting an export.

These numbers define the invented scenario. They are not recommendations for your application’s size, delivery commitment, or staffing.

The proposal to review

Add an Export button to the customer dashboard. The browser sends an organization ID to a new endpoint. The endpoint checks that the requester is logged in, loads that organization’s records, creates the CSV, and uploads it to file storage before returning a download URL.

Save the URL on the user’s profile so the dashboard can show their latest export. The URL stays valid indefinitely. If the request times out, display an error and ask the user to click Export again.

Include all available fields to avoid follow-up requests. Add a test showing that a logged-in user receives a download link. After launch, add recurring exports and a configurable export builder.

The proposal is intentionally incomplete. Tell candidates this directly. You are asking them to improve it, not discover whether the interviewer secretly believes it is already correct.

The requested response

Ask for four things:

1. Identify the three changes you would prioritize before this first release. Explain the consequence each addresses.
2. Recommend a release approach that fits the supplied constraints. State what you would leave out.
3. Name one unanswered question whose answer could change your recommendation.
4. Describe evidence you would want before approving the change, including tests or measurements.

No implementation is required. Candidates can use a sketch, bullets, or a short document. They can state assumptions explicitly, but should not quietly change a supplied requirement to make their preferred architecture fit.

Look for priorities tied to the proposal

A useful review distinguishes a release blocker from a question, an improvement, and future work. Finding twelve concerns is not automatically stronger than identifying three consequential ones and proposing a coherent response.

For this packet, access is a concrete issue. The proposal trusts a browser-supplied organization ID and describes only a login check. A candidate should connect that gap to the requirement that administrators access only their own organization’s records. “Add security” is less informative than describing where authorization needs to apply.

Generation inside the web request deserves investigation too. The supplied record count and missing measurements do not prove that synchronous generation will fail. They do mean the proposal has not established that it can complete reliably within the request’s limits. Notice whether the candidate distinguishes an observed problem from a risk that needs evidence.

The indefinite link and unresolved loss-of-access behavior expose a missing product decision. A good review can ask who should be allowed to download a completed file and for how long. It should not invent a retention rule and present that preference as a requirement the packet already supplied.

Google’s code-review guidance asks reviewers to examine design, functionality, edge cases, and complexity, including unnecessary work for speculative future needs. Those are useful review concerns here. The guidance addresses engineering reviews, not the validity of this hiring exercise.

In this case, a configurable export builder can wait: it is not required for the first release. A candidate who spends the review designing it should explain why it deserves time ahead of the stated access and delivery questions.

Allow more than one defensible release plan

Grade the fit between the plan and the constraints, not agreement with your favorite implementation. Write down plausible alternatives before interviewing so reviewers do not turn an unstated preference into a requirement.

One candidate might propose background generation using the existing workers, a record of each export request, private storage, and an authorized download route. They could explain how repeated requests are handled, how the user sees readiness or failure, and which measurements establish the ten-minute goal.

Another might first propose a smaller release for customers below an explicit size limit, while measuring generation before deciding how much work belongs in a background job. That answer needs a candid limitation: it does not yet serve the largest customer. The candidate must seek agreement on reduced scope rather than claim the original requirement is satisfied.

Either plan still needs the relevant access checks and an explicit decision about file access over time. A simpler implementation does not excuse missing requirements. A more elaborate implementation does not earn extra credit just because it includes more components.

Compare the reasoning behind the plans. Does the candidate explain what can go wrong, who would notice, and what evidence changes the decision? Do they name the cost of their own recommendation? Those observations are more useful than a tally of architecture terms.

Record justified disagreements too. If a candidate challenges the ten-minute goal or the one-week schedule, ask what they would tell the product owner and what alternative they would offer. Challenging a constraint is different from overlooking it.

Use the same core follow-up questions

Plan the discussion before seeing a candidate’s answer. Keep the central questions consistent, while using clarifying questions to understand the reasoning actually presented.

OPM’s structured-interview guidance describes predetermined questions and common rating standards. For this exercise, you can apply that principle with a short discussion guide:

• Which issue would you resolve first, and why does it come before the others?
• What would make you choose a different release approach?
• Where does your plan depend on information we have not supplied?
• What would you ask another specialist to review?

Then give every candidate the same additional fact: “Product confirms that administrators who lose access must no longer be able to download previously generated exports.” Ask what this changes in their plan and what needs testing.

Tell candidates in advance that the conversation includes an additional requirement. It should be an opportunity to revise a decision, not a surprise performance trick. Record whether they explain a change, identify an existing safeguard, or need more information.

Do not improvise increasingly difficult scenarios for candidates you find impressive. If you give one person a regional outage and another a wording change, the resulting scores describe different exercises.

Anchor scores to things you observed

Define what each score means before the debrief. A criterion should produce a note another reviewer can examine, rather than a label such as “senior presence.”

The table below is a suggested starting point. Adapt the dimensions to the job and pilot the anchors. “Insufficient evidence” should remain available when the exercise or discussion did not reveal enough to judge.

An evidence note could read: “Identified that the organization ID needs authorization; asked for a test using an administrator from a different organization.” Another could read: “Recommended a queue, but did not connect it to request duration or explain failure handling.”

Keep these observations separate from the final hiring decision. One exercise samples one part of the role. It does not settle coding ability, all collaboration skills, or readiness for every senior responsibility. Our structured scorecard guide covers how to organize criteria across the wider process.

Calibrate the reviewers before using the exercise

Test whether reviewers understand the packet and apply the anchors consistently. Have colleagues complete it, note their actual effort, and score their responses independently before discussing them.

When reviewers disagree, inspect the reason. Did one reward naming a particular service? Did another assume a requirement absent from the packet? Was the response ambiguous, or was the rating description too broad? Repair the exercise or guide before candidates encounter the same problem.

Keep a version of the packet and discussion guide with each assessment. If you change the requirements between interviews, record the change and consider whether earlier scores remain comparable. Do not silently improve the instructions halfway through a hiring round.

Ask pilot participants where they lacked context and which instructions consumed unnecessary time. Remove work that does not contribute to a stated criterion. This pilot helps you improve administration; it is not proof of predictive validity or freedom from bias.

Assign reviewers who understand the decisions being assessed. If the exercise turns into a specialist security examination, either involve a qualified reviewer and make that requirement explicit or narrow the task. The hiring manager owns the fit between the role, the exercise, and the panel.

Organize the design-review stage in Kit

Keep the brief, criteria, and reviewer observations connected to the candidate’s stage. The hiring team still has to author a relevant exercise and decide what the evidence supports.

In Kit, put the supplied document in a Work Sample private brief and collect the candidate’s written critique as an upload or response link. Assign reviewers and scoring criteria, then schedule the discussion as a Live Interview. Criteria support descriptions, weights, and scales; your team supplies the rubric.

During an active review round, reviewers submit their own assessment before seeing their peers’ completed reviews. This supports the review sequence; it does not establish fairness or correctness. Kit does not supply a validated design-review test or automatically judge architecture.

Finalize the Work Sample brief and rubric before inviting candidates: its assessment contract locks when the first candidate reaches the stage. If you configure compensation, Kit tracks the payout request; your team sends the money.

Start with one responsibility, one supplied proposal, and a short list of decisions the candidate should be able to explain. Pilot it with your reviewers, repair the confusing parts, and tell candidates exactly what work you are asking them to do.