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Technical interviews should include code review

Code-review interviews reveal how candidates read context, prioritize consequence, communicate evidence, and improve a change.

JP
JP Casabianca
Designer/Engineer · Bogotá

Most engineers spend more time reading and changing code than writing a solution from nothing.

They review pull requests, debug inherited assumptions, compare an implementation with a product contract, ask for missing tests, notice an accessibility regression, and decide which concern matters before merge. AI-assisted development makes that review skill more important, not less.

A technical interview should include that work. Give the candidate a small diff, enough product context to reason about consequence, and time to review silently before discussing priorities with an interviewer.

The goal is not to hide trivia in the patch. It is to observe how someone builds a risk model, communicates evidence, and changes their mind when new context appears.

Good review is a technical skill and a collaboration skill in the same artifact.

01 · OrientRead intent and context

Candidate understands the product promise, affected path, constraints, and diff shape.

02 · ReviewPrioritize consequence

Correctness, security, accessibility, data, performance, and maintainability are ranked.

03 · CollaborateImprove the change

Candidate explains evidence, asks questions, responds to context, and proposes a bounded fix.

Figure 1: A code-review interview follows the work engineers actually do.

Choose a job-relevant diff

The patch should resemble the role's real decisions and remain small enough to understand during the interview.

I would pressure-test that decision with four questions:

  • Which code does the role review?
  • Which consequence is realistic?
  • Can context fit on one page?
  • Is the language essential?

The failure mode here is using a contrived puzzle with hidden syntax traps. In engineering interviews where the daily job includes reading unfamiliar code, finding risk, clarifying intent, giving feedback, validating AI-assisted changes, and improving work with other people, that can hide the exact boundary a reviewer or teammate needs to understand. My working artifact would be a bounded diff with product and system brief. I want it close enough to the implementation that it can change the work, not created afterward to decorate the story.

The result I would look for is a review task with stronger job relevance. That is a narrower claim than saying the whole system improved, but it is also one I can verify and defend.

In practice, I would put a bounded diff with product and system brief beside the question “Which code does the role review?” before the first implementation review. The next pass would use “Which consequence is realistic?” to test the boundary, then “Can context fit on one page?” to expose the state most likely to be missed. I would keep “Is the language essential?” for the release check because it asks whether the decision still holds outside the ideal path. The work is ready to move when the artifact can explain the choice and the observed result supports a review task with stronger job relevance.

Provide the product promise

Candidates cannot prioritize technical risk without knowing what the interface or service must make true.

The practical review starts here:

  • What is the user doing?
  • Which state is critical?
  • What cannot duplicate or disappear?
  • What counts as complete?

Those questions keep grading product judgment while withholding product context from becoming the default. I would capture the decision in a short product contract above the diff, then use it while the work is still cheap to change. For real-work technical interviewing, the artifact should make ownership, constraint, and next action visible without requiring a private explanation.

Success would look like review comments connected to real consequence. If I cannot point to that evidence, I have a direction, not a finished decision.

The implementation move is to make a short product contract above the diff part of the working surface. I would use it to answer “What is the user doing?” while scope is still flexible, and “Which state is critical?” before code or content becomes expensive to unwind. During QA, “What cannot duplicate or disappear?” and “What counts as complete?” become concrete checks rather than discussion prompts. That sequence turns real-work technical interviewing into something the team can operate and gives me a specific outcome to report: review comments connected to real consequence.

  1. SilentTen-minute review

    Read the brief and diff, leave notes, and choose the highest-risk question.

  2. DiscussTwenty-minute calibration

    Explain priorities, uncertainty, and what evidence would change the recommendation.

  3. ChangeFifteen-minute follow-up

    Adjust one test, contract, or implementation detail together.

Figure 2: The interview can reveal depth without requiring a large take-home.

Seed several kinds of issue

The diff should contain a mix of obvious, subtle, high, and low consequence concerns without one secret answer.

Before implementation, I would answer:

  • Is there a correctness issue?
  • Is there a trust boundary?
  • Is one issue intentionally minor?
  • Can multiple fixes be valid?

The artifact is an evaluator map of seeded risks and acceptable alternatives. Its job is to expose the tradeoff early enough that design, engineering, support, or product can disagree with something concrete. The common trap is turning the review into spot-the-bug; it moves uncertainty downstream and makes the final interface carry a problem the system never resolved.

For me, the useful receipt is evidence of prioritization rather than recall. That connects a structured code-review interview as a practical signal of engineering judgment to an observable result instead of a process claim.

I would test this with one typical case and one boundary case. The typical case should make “Is there a correctness issue?” easy to answer. The boundary should force a decision about “Is there a trust boundary?” and “Is one issue intentionally minor?.” I would record both in an evaluator map of seeded risks and acceptable alternatives, including the part that stayed unresolved after the first pass. The final check, “Can multiple fixes be valid?,” is where the artifact earns its place: it either supports evidence of prioritization rather than recall, or it shows exactly why another iteration is needed.

Give quiet reading time

Candidates need a short uninterrupted window to orient before they perform reasoning aloud.

I would use these prompts during the working review:

  • How long is the diff?
  • Can comments be written?
  • Is screen zoom available?
  • Can a printed or local copy be used?

If the team slips into requiring instant narration while the candidate is still parsing, the product can still look complete while its operating rule stays ambiguous. I would make a silent review phase with accessible materials the shared reference and keep it small enough to update as evidence changes.

The standard is a fairer view of independent technical reading. That tells me whether the decision helped the product, not merely whether the document was completed.

The working sequence is small: draft a silent review phase with accessible materials, review it against “How long is the diff?,” implement the narrowest useful path, and then return with evidence for “Can comments be written?.” I would use “Is screen zoom available?” to inspect product consequence and “Can a printed or local copy be used?” to decide whether the result is stable enough to ship. This keeps requiring instant narration while the candidate is still parsing visible as a known risk and makes a fairer view of independent technical reading the release receipt rather than a hopeful conclusion.

SignalDecisionWorking note
SignalFind meaningful riskCandidate connects code behavior to user, data, access, money, or operational consequence.
EvidenceExplain whyComment is specific, proportionate, testable, and open about uncertainty.
ActionMove work forwardCandidate proposes a useful fix, question, test, follow-up, or merge condition.
Figure 3: The rubric should reward prioritization, not comment count.

Ask for the merge decision

A review becomes concrete when the candidate says what blocks merge, what can follow, and what evidence is missing.

I would pressure-test that decision with four questions:

  • Would they approve?
  • Which issue blocks?
  • Which issue is optional?
  • What check would change the decision?

The failure mode here is rewarding a long list of undifferentiated comments. In engineering interviews where the daily job includes reading unfamiliar code, finding risk, clarifying intent, giving feedback, validating AI-assisted changes, and improving work with other people, that can hide the exact boundary a reviewer or teammate needs to understand. My working artifact would be a merge, request-changes, or follow-up recommendation. I want it close enough to the implementation that it can change the work, not created afterward to decorate the story.

The result I would look for is clear consequence-based judgment. That is a narrower claim than saying the whole system improved, but it is also one I can verify and defend.

In practice, I would put a merge, request-changes, or follow-up recommendation beside the question “Would they approve?” before the first implementation review. The next pass would use “Which issue blocks?” to test the boundary, then “Which issue is optional?” to expose the state most likely to be missed. I would keep “What check would change the decision?” for the release check because it asks whether the decision still holds outside the ideal path. The work is ready to move when the artifact can explain the choice and the observed result supports clear consequence-based judgment.

Observe communication quality

Strong review feedback is specific, respectful, proportionate, and aimed at moving the work forward.

The practical review starts here:

  • Does the comment name behavior?
  • Is uncertainty explicit?
  • Can the author act on it?
  • Is severity appropriate?

Those questions keep scoring confidence or tone as a proxy for correctness from becoming the default. I would capture the decision in a communication rubric with behavioral anchors, then use it while the work is still cheap to change. For real-work technical interviewing, the artifact should make ownership, constraint, and next action visible without requiring a private explanation.

Success would look like better evidence of collaborative engineering. If I cannot point to that evidence, I have a direction, not a finished decision.

The implementation move is to make a communication rubric with behavioral anchors part of the working surface. I would use it to answer “Does the comment name behavior?” while scope is still flexible, and “Is uncertainty explicit?” before code or content becomes expensive to unwind. During QA, “Can the author act on it?” and “Is severity appropriate?” become concrete checks rather than discussion prompts. That sequence turns real-work technical interviewing into something the team can operate and gives me a specific outcome to report: better evidence of collaborative engineering.

Add one piece of new context

A realistic review changes when the author explains a constraint, provider behavior, or rollout plan.

Before implementation, I would answer:

  • Can the candidate update priorities?
  • Do they defend evidence without ego?
  • What question becomes more important?
  • What concern can close?

The artifact is a scripted context reveal. Its job is to expose the tradeoff early enough that design, engineering, support, or product can disagree with something concrete. The common trap is treating any changed opinion as weakness; it moves uncertainty downstream and makes the final interface carry a problem the system never resolved.

For me, the useful receipt is evidence of adaptable reasoning. That connects a structured code-review interview as a practical signal of engineering judgment to an observable result instead of a process claim.

I would test this with one typical case and one boundary case. The typical case should make “Can the candidate update priorities?” easy to answer. The boundary should force a decision about “Do they defend evidence without ego?” and “What question becomes more important?.” I would record both in a scripted context reveal, including the part that stayed unresolved after the first pass. The final check, “What concern can close?,” is where the artifact earns its place: it either supports evidence of adaptable reasoning, or it shows exactly why another iteration is needed.

Make a small change together

A short follow-up edit tests whether the candidate can turn review insight into implementation or verification.

I would use these prompts during the working review:

  • Which change is bounded?
  • Can a test expose it?
  • Can the candidate explain the tradeoff?
  • Does collaboration improve the result?

If the team slips into expanding the exercise into a second coding interview, the product can still look complete while its operating rule stays ambiguous. I would make a fifteen-minute paired fix or test the shared reference and keep it small enough to update as evidence changes.

The standard is a closed loop from critique to improvement. That tells me whether the decision helped the product, not merely whether the document was completed.

The working sequence is small: draft a fifteen-minute paired fix or test, review it against “Which change is bounded?,” implement the narrowest useful path, and then return with evidence for “Can a test expose it?.” I would use “Can the candidate explain the tradeoff?” to inspect product consequence and “Does collaboration improve the result?” to decide whether the result is stable enough to ship. This keeps expanding the exercise into a second coding interview visible as a known risk and makes a closed loop from critique to improvement the release receipt rather than a hopeful conclusion.

Calibrate reviewers

Interviewers should compare behavior against the role rubric and sample evidence before evaluating candidates.

I would pressure-test that decision with four questions:

  • Which risks matter most?
  • Which alternatives are valid?
  • How are accommodations handled?
  • How is disagreement recorded?

The failure mode here is assuming experienced engineers automatically interview consistently. In engineering interviews where the daily job includes reading unfamiliar code, finding risk, clarifying intent, giving feedback, validating AI-assisted changes, and improving work with other people, that can hide the exact boundary a reviewer or teammate needs to understand. My working artifact would be a reviewer calibration session with sample comments. I want it close enough to the implementation that it can change the work, not created afterward to decorate the story.

The result I would look for is more reliable evidence across interview panels. That is a narrower claim than saying the whole system improved, but it is also one I can verify and defend.

In practice, I would put a reviewer calibration session with sample comments beside the question “Which risks matter most?” before the first implementation review. The next pass would use “Which alternatives are valid?” to test the boundary, then “How are accommodations handled?” to expose the state most likely to be missed. I would keep “How is disagreement recorded?” for the release check because it asks whether the decision still holds outside the ideal path. The work is ready to move when the artifact can explain the choice and the observed result supports more reliable evidence across interview panels.

Share a useful outcome

Candidates should receive closure and the team should retain observations, not vague labels.

The practical review starts here:

  • What evidence was observed?
  • Which role behavior did it support?
  • What uncertainty remains?
  • Can feedback be shared safely?

Those questions keep recording strong or weak with no behavioral basis from becoming the default. I would capture the decision in an observation-first interview note and candidate feedback line, then use it while the work is still cheap to change. For real-work technical interviewing, the artifact should make ownership, constraint, and next action visible without requiring a private explanation.

Success would look like a more humane and defensible hiring decision. If I cannot point to that evidence, I have a direction, not a finished decision.

The implementation move is to make an observation-first interview note and candidate feedback line part of the working surface. I would use it to answer “What evidence was observed?” while scope is still flexible, and “Which role behavior did it support?” before code or content becomes expensive to unwind. During QA, “What uncertainty remains?” and “Can feedback be shared safely?” become concrete checks rather than discussion prompts. That sequence turns real-work technical interviewing into something the team can operate and gives me a specific outcome to report: a more humane and defensible hiring decision.

What I would show in the work

The public version needs evidence from the work itself. For this topic, the first five artifacts I would reach for are:

  • a bounded diff with product and system brief
  • a short product contract above the diff
  • an evaluator map of seeded risks and acceptable alternatives
  • a silent review phase with accessible materials
  • a merge, request-changes, or follow-up recommendation

I would not publish all five at equal weight. One should orient the reader, one should reveal the hardest tradeoff, and one should prove the result. The others can live in a downloadable note or appear as supporting frames. That edit matters because a structured code-review interview as a practical signal of engineering judgment becomes harder to understand when every process detail is treated as equally important.

I would also show one rejected direction. The useful version is specific: which option looked attractive, which constraint made it wrong, and what evidence supported the narrower choice. That gives an engineering manager something real to question and keeps the case study from reading like the final answer was obvious from the beginning.

code-review-interview.md
# observation
flags duplicate payment risk
Connects retry path to missing idempotency and asks for provider contract evidence.

# interaction re-ranks after context Accepts that UI copy is follow-up; keeps mutation safety as merge blocker.

# inference strong consequence-based review Evidence supports role behavior; confidence and remaining uncertainty recorded.

Figure 4: A code-review scorecard separates observations from hiring inference.

Resource path

The practical follow-up I would build is a code-review interview kit with role context, bounded diff, product promise, seeded risks, review rubric, accessibility accommodations, interviewer prompts, follow-up change, and evidence capture. I am treating that as a resource backlog item, not pretending the adjacent downloads below are the same artifact. The related cards cover useful pieces of the workflow today; this specific file should only be published when its examples, fields, and instructions are complete.

The first version should stay concise: context, constraint, decision, evidence, owner, and follow-up. Its value would come from helping someone repeat this exact review, not from adding another generic PDF to the site.

Review checklist

The article-specific review questions are:

  • Which code does the role review?
  • What is the user doing?
  • Is there a correctness issue?
  • How long is the diff?
  • Would they approve?
  • Does the comment name behavior?
  • Can the candidate update priorities?
  • Which change is bounded?
  • Which risks matter most?
  • What evidence was observed?

I would add two editorial checks before publishing: can a recruiter find the point in the first minute, and can an engineer trace at least one claim to an implementation or production receipt? If either answer is no, the article needs another edit.

Implementation notes

For real-work technical interviewing, I would write the implementation note before polish. It would name the changed surface, source of truth, owner, failure boundary, and verification path. Those details prevent the principle from floating above the actual code or operational workflow.

The proof signals I care about are specific to this article:

  • better evidence of collaborative engineering
  • evidence of adaptable reasoning
  • a closed loop from critique to improvement
  • more reliable evidence across interview panels
  • a more humane and defensible hiring decision

I would choose two or three of those signals for the first release rather than instrumenting everything. The strongest pair usually combines one direct behavior check with one operating check: a route and a data query, a keyboard path and a support state, a handler replay and a reconciliation result, or a migration count and a rendered screen.

The follow-up belongs in the note before shipping. It should say what remains temporary, what evidence would trigger another pass, and who owns that decision. That is how the first version stays intentionally narrow without making the boundary invisible.

Case-study packaging

I would structure the case-study version around the four visual lessons already established:

  • A code-review interview follows the work engineers actually do.
  • The interview can reveal depth without requiring a large take-home.
  • The rubric should reward prioritization, not comment count.
  • A code-review scorecard separates observations from hiring inference.

The opening frame explains the product pressure. The middle two show the decision moving through the system. The last frame is the receipt: what was checked, what held, and what remained unresolved. That order lets the reader move from product judgment into implementation detail without reconstructing the whole project first.

I would include one caveat tied to engineering interviews where the daily job includes reading unfamiliar code, finding risk, clarifying intent, giving feedback, validating AI-assisted changes, and improving work with other people: a data limit, rollout boundary, unsupported state, external dependency, or result that is still directional. A precise caveat makes the evidence easier to trust because it shows where the claim stops.

The final test is whether the page creates a better conversation. If the artifact helps someone ask a sharper question about product judgment, implementation detail, or release proof in a live interview, it belongs in the story.

Interview angle

In an interview, I would explain this through a structured code-review interview as a practical signal of engineering judgment. The story should start with the product pressure, then move into the system constraint, the artifact, and the proof. That order keeps the answer grounded. It also gives the interviewer several places to go deeper: data, frontend architecture, design systems, support, migration, accessibility, or release process.

The strongest version of the answer includes a tradeoff. I want to be able to say what I chose, what I left alone, and how I knew the work helped. That is more credible than presenting every project as a clean win.

The hiring signal

A code-review interview creates a useful hiring signal because it shows how a candidate reads context, prioritizes consequence, communicates uncertainty, and improves a change—not only how quickly they can produce code from a blank file.

That is the level I want this site to communicate. The work should show taste, but it should also show operating judgment. It should make me look like someone who can enter a real product system, understand the messy middle, ship the useful version, and leave enough proof for the next person to trust it.

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