Traditional algorithm interviews often fail to predict how well an engineer will perform on a team. A Code Review Interview presents candidates with a realistic pull request containing intentional flaws—performance bottlenecks, security vulnerabilities, edge-case oversights, or poor TypeScript design.
Why Code Review Interviews Outperform Puzzle Puzzles
- Mirrors Daily Engineering: Developers spend significant time reviewing peer pull requests.
- Evaluates Practical Depth: Tests knowledge of security (SQL injection, auth bugs), performance (N+1 queries, memory leaks), and maintainability.
- Tests Communication Skills: Observes how constructively candidates phrase feedback and suggest refactored alternatives.
How to Structure a Code Review Exercise
- Provide Context: Give candidates a brief user story or bug report explaining what the pull request is intended to accomplish.
- Include 3-5 Specific Flaws: Mix bug categories (e.g. 1 security bug, 1 performance issue, 1 missing error handling case).
- Allow Live Editing: Ask the candidate to not only point out the flaws but refactor the code live in the editor.
A Reusable 45-Minute Structure
- Context — 5 minutes: Explain the product, the user story, and the constraints behind the change.
- First read — 10 minutes: Ask the candidate to scan the code without editing and describe what they would verify first.
- Findings — 15 minutes: Have them list findings, separate blockers from suggestions, and explain the risk of each.
- Focused refactor — 10 minutes: Require one small change that addresses the highest-value issue.
- Debrief — 5 minutes: Ask what they would review automatically in CI and what still needs human judgment.
What a Strong Candidate Does
A strong candidate does not need to find every planted flaw. They establish the intended behavior, ask clarifying questions, identify the highest-risk issue first, and explain why the change matters. They also distinguish a correctness bug from a preference, propose a bounded fix, and describe how they would verify it.
Interviewer Mistakes to Avoid
- •No context: A mysterious snippet rewards pattern matching instead of engineering reasoning.
- •Too many hidden traps: It becomes a test of spotting planted keywords rather than prioritization.
- •Style-only feedback: Naming conventions can be discussed later; correctness, security, and data loss come first.
- •No rubric: Decide in advance what strong communication and sound prioritization look like for the role.
For a backend-focused version, see Backend Code Review Interview: API, Database & Security Exercises. For a practical prompt library, use Code Review Interview Questions and Exercises and the live exercise library.
Run Code Review Interviews Live
Frequently Asked Questions
Why are code review interviews gaining popularity?
Code review interviews mirror true day-to-day engineering tasks: reviewing code written by peers, identifying security/performance bugs, and communicating constructive feedback.
How long should a code review interview exercise take?
A focused 30-to-45-minute format is usually enough to assess prioritization, technical reasoning, and communication. Give the candidate context, a bounded change, and an explicit request to explain and improve the code.
Should a candidate refactor the code during a code review interview?
Ask for one small, high-value refactor after the candidate explains the findings. This keeps the exercise focused on judgment and trade-offs instead of turning it into an open-ended debugging session.
Conduct Live Coding Interviews in the Browser
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