The code review interview round: what it is and how to prepare

Published 1 November 2026 · 3 min read

In a code review interview you don't write a solution from scratch. You read code someone else wrote, find what's wrong and explain how you'd improve it. As AI writes more of the code, reviewing it well matters more, and more loops now include a round like this. Formats vary a lot, so here are the ones candidates report and how to prepare for each.

The formats you might get

• Comment on a diff. HackerRank's interview tool has a dedicated code review question type. The interviewer shares "code written by someone else", and you add comments to specific lines. Interviewers can attach grading rubrics that only they can see (HackerRank documentation).
• Review a pull request against requirements. One candidate described getting "a PR and the feature requirements" and being asked for a feedback summary of the engineer's code, with an AI assistant allowed (r/leetcode).
• Walk through an unfamiliar codebase. An engineer with 7 years of experience described a "code review" round where they had to explain how a frontend feature worked in a new codebase, guiding the interviewer on screen share (r/ExperiencedDevs).
• Critique code, then improve it. Engineering manager candidates at Google report a dedicated code review or comprehension round. One reply said it lasts 45 minutes, and another said the interviewer may ask you to rewrite part of the solution (r/EngineeringManagers).

Ask your recruiter which format you'll get. A diff review and a live codebase walkthrough need different practice.

What interviewers look for

Replies from people who have run or taken these rounds agree on a few points:

• A method, not a list of nits. One reply framed the code as "a PR from a mid level engineer you trust but who occasionally gets a little too clever". The interviewer is checking that you know what clean code looks like and can take it apart methodically.
• Function first. One reply's checklist starts with whether the code actually works as intended, before style. The same reply warned that 45 minutes goes quickly, so a fixed order helps.
• Judgment about what matters. For manager roles, a reply said the round is "more about how you reason about code quality and team practices than catching nits" (r/EngineeringManagers).
• Clear communication. In every format you're explaining your findings out loud, often while the interviewer types or drives.

A review order that works under time pressure

1. Requirements. Does the code do what the ticket or prompt asks? Note anything missing.
2. Correctness. Off-by-one errors, empty and null input, wrong conditions, shared state.
3. Error handling. What happens when a call fails, a record is missing or input is invalid?
4. Tests. Which important cases have no test?
5. Security and data. Unvalidated input, secrets in code, unsafe queries.
6. Performance. Repeated work inside loops, unbounded queries, missing pagination.
7. Readability. Naming, function size, duplication. Mention these last and mark them as minor.

Label each comment as blocking or minor, and give a reason with each one. "This throws on an empty list because…" beats "Handle empty lists".

How to prepare

• Review real pull requests. Pick merged PRs in an open-source project you know, write your own review, then compare it with the maintainers' comments.
• Practice navigation. Find an entry point, follow a request through the code and summarise it in two minutes. If you're on someone else's screen, it's fine to ask for a few minutes to read first.
• Time-box yourself. Give yourself 30 minutes on a 200-line diff and try to cover the whole checklist before going deep on any one issue.
• Be ready to write code. Some interviewers follow up with "how would you fix it?", so practice rewriting the worst function you found.
• If AI is allowed, check what it says. Use it to summarise a diff or explain a function, then confirm each claim against the code before you repeat it.

Code review skills overlap with the newer AI rounds. See Google's code comprehension interview and how to use the AI without hurting your score.

Sources

• HackerRank: Code Review Questions in Interviews (product documentation, checked 1 November 2026)
• r/ExperiencedDevs: Just failed a code review interview as 7 YOE (February 2026)
• r/EngineeringManagers: Google engineering manager code review round (June 2026)
• r/EngineeringManagers: Google code review/comprehension interview for L6 EM (October 2026)
• r/leetcode: Stripe and Meta new AI interview experience (July 2026, includes a PR review report)