Quick answer: What code review skills are senior engineers judged on, and how do I improve?
- What to look for — correctness, security, design, tests, readability — in that order.
- How to say it — specific, kind, explain why, label nits as optional.
- Speed and size — small PRs, reviews within a working day, automation for style.
- Quality systems — tests, linters, static analysis and CI gates, not heroic reviewers.
- Why it matters now — AI-generated code makes careful review the bottleneck skill.
Key takeaways
- Good reviewers catch bugs and design problems; poor ones argue about formatting.
- Review speed affects team throughput as much as review quality.
- Small pull requests get better reviews — ask for them and write them.
- Automate style and simple checks so humans focus on what matters.
- Reviewing AI-generated code well is fast becoming a hiring criterion.
Picture two reviews of the same pull request — a new endpoint for exporting customer invoices. The first reviewer leaves fourteen comments about variable names, blank lines and import order, and approves. The second leaves three: the endpoint doesn't check that the invoices belong to the requesting customer; the export loads every invoice into memory and will fail for large accounts; and there's no test for an empty date range. They approve after the fixes and let the linter handle formatting. Teams promote the second reviewer. Code review is where senior engineering judgement becomes visible.

Why code review is a career skill
Code review is how teams share knowledge, catch defects and keep systems coherent. For engineers moving into senior and tech lead roles, review quality is one of the clearest signals of judgement — what you notice, what you let go and how you say it. Google's public engineering practices describe the goal as improving the overall health of the codebase over time, not perfection in every change.1
The skill is becoming more important. Stack Overflow's 2025 survey found most developers use or plan to use AI tools, and that their top frustration is code that's "almost right, but not quite".5 As more code is generated, careful review becomes the bottleneck — and the differentiator. Senior roles that rely on this judgement pay well: software architects in India typically earn ₹32.1–35.5 lakh.7
- Developers using or planning to use AI tools (Stack Overflow, 2025)
- 84%
- Developers frustrated by AI output that's "almost right" (Stack Overflow, 2025)
- 66%
- A common upper limit for a first review response
- 1 day
- The pull-request size that gets the best reviews
- Small
How review skills are assessed
| Setting | Example | What they look for |
|---|---|---|
| Review exercise in interviews | "Review this pull request." | Priority of issues found; tone |
| Behavioural questions | "Tell me about a review disagreement." | Collaboration, influence |
| Promotion reviews | Peer feedback on your reviews | Usefulness, speed, mentoring |
| Team metrics | Review turnaround, change failure rate | Effect on delivery and quality |
Table: How code review skills are assessed (editorial summary)
What great reviewers look for

Correctness
Logic, edge cases, error handling, concurrency, data integrity.
Security
Authorisation, input validation, injection, secrets — OWASP's Code Review Guide is a good checklist.6
Design
Fit with the system, simplicity, boundaries, duplication and future change.
Tests
Coverage of the change and its failure modes; tests that would actually catch regressions.
Readability
Names, structure and comments that explain why — not formatting, which tools should enforce.
Operability
Logging, metrics, feature flags and safe rollout for risky changes.
How to give feedback that lands

- Read the description first — Understand the goal before the diff.
- Start with the big picture — Design and correctness before details.
- Be specific and explain why — "This query runs per item; with 500 items that's 500 calls. Could we batch it?"
- Separate blocking from optional — Label nits; don't block on preferences.
- Ask, don't accuse — "What happens if the list is empty?" invites thinking.
- Respond quickly — Google's guidance stresses speed because slow reviews block teams.2
Worked example: rewriting review comments
| Weak comment | Strong comment |
|---|---|
| "This is wrong." | "This returns invoices for any customer ID passed in. Can we check it matches the authenticated user? Otherwise users could read others' invoices." |
| "Rename this." | "Nit (optional): data is vague here — pendingInvoices would make the loop clearer." |
| "Add tests." | "Could we add a test for an empty date range? That path returns null today and the caller doesn't handle it." |
| "Too slow." | "This loads all invoices into memory; large accounts have 200k+. Streaming or pagination would avoid timeouts." |
Table: Weak vs strong code review comments (illustrative)
Code quality systems, not heroes
Quality shouldn't depend on one vigilant reviewer. Teams that ship reliably automate formatting and linting, run static analysis and tests in CI, require small pull requests, and track delivery outcomes — the kind of practices DORA's research links to better software delivery performance.3 Reviewing a few hundred lines at a time is widely recommended because reviewers' effectiveness falls on large changes.4
Code review interview questions, with how to answer them
"What do you look for first in a review?"
Whether the change does what it should, safely: correctness, security and design — then tests and readability.
"How do you handle a disagreement in review?"
Clarify the concern, explain trade-offs, look for data or a quick spike, and if still stuck, involve a third person or follow team conventions — then move on.
"A teammate's PR is 3,000 lines. What do you do?"
Ask to split it, or review in a call with the author walking through it; suggest stacking smaller PRs in future.
"How do you review AI-generated code?"
The same as any code, with extra attention to plausible-looking mistakes: missing edge cases, incorrect API use, security gaps and licence concerns.
"How do you keep reviews fast?"
Small PRs, clear descriptions, automation for style, review slots in the day and responding to first review within hours.
"What is technical debt and how do you manage it?"
Shortcuts that make future change harder. Make it visible, pay it down alongside features, and stop adding it where it costs most.
Could you pass the Code Review and Code Quality Certification today?
Hiring managers test judgement with scenarios like this one. Answer it before you open the explanation — the test has 15 of them, 15 minutes, 70% to pass.
What's a reviewer's best response to a PR with 3,000 changed lines?
- Ask the author to split it into smaller, focused PRs
- Approve it quickly
- Review only the first file
- Ignore it
Show the answer
A. Ask the author to split it into smaller, focused PRs — Huge PRs hide bugs and slow everyone down.
- 01Reviewing code
- 02Keeping quality high
- 03Engineering practices and tooling
Free, no sign-up. Pass and you become a Code Review and Code Quality, with a credential ID employers can verify. Every answer is explained either way.
How code review has changed
| Period | What happened | What teams expected |
|---|---|---|
| 2005–2010 | Formal inspections and email patches | Heavy, infrequent reviews |
| 2011–2016 | Pull requests on GitHub and tools like Gerrit | Lightweight review of every change |
| 2017–2021 | CI, linters and static analysis widespread | Humans focus on design and correctness |
| 2022–2024 | Trunk-based development, small PRs | Fast, frequent reviews |
| 2025–2027 | AI writes and pre-reviews code | Human judgement on AI-generated changes |
Table: How code review has changed (editorial summary)
Practice tasks
- Review open source — Read reviews on a well-run open-source project; note what maintainers catch.
- Rewrite your comments — Take five past comments and make them specific, kind and justified.
- Self-review first — Review your own PR before requesting review, every time.
- Automate — Set up formatting, linting and a test gate in CI for a project.
- Review AI output — Generate a feature with an assistant and write a full review of it.
Where review skills take your career
| Role (India) | Typical pay | Review's part |
|---|---|---|
| Software engineer | ₹9.3–10.2 lakh | Reviewing peers' changes |
| SDET | ₹14.7–16.3 lakh | Reviewing tests and testability |
| Software architect | ₹32.1–35.5 lakh | Reviewing designs and critical changes |

Table: Roles where code review matters and typical pay in India (AmbitionBox, October 2026; indicative)
A four-week plan

- Week 1: Read the guides — Google's engineering practices and OWASP's Code Review Guide.
- Week 2: Practise — Review ten open-source PRs privately; compare with maintainers' comments.
- Week 3: Improve your team's system — Add automation and a PR template.
- Week 4: Prove it — Take the Code Review and Code Quality Certification.
Related: Secure Coding Fundamentals, AI-Assisted Software Development and Git and GitHub.
How code review shows up day to day
- Daily review slots — reviewing teammates' pull requests within hours, not days.
- Self-review — reading your own diff before asking anyone else.
- Design conversations — moving long review threads into a quick call and recording the decision.
- Mentoring — explaining the "why" behind comments for junior engineers.
- Quality tooling — maintaining linters, formatters and CI checks.
- AI-generated changes — reviewing them with the same rigour as human code.
Mistakes that hurt reviewers' reputations
- Nitpicking while missing real bugs.
- Harsh or vague comments.
- Slow reviews that block teammates.
- Rubber-stamping large PRs.
- Using review to gatekeep instead of teach.
How we know
Guidance draws on Google's public engineering practices (code review and review speed), DORA's research, SmartBear's peer-review best practices and OWASP's Code Review Guide; AI-use figures from Stack Overflow's 2025 survey; pay from AmbitionBox (read October 2026). Assessment settings and the history table are editorial summaries. Science of Apps publishes the free certification linked here. Last reviewed October 2026.
Key terms, defined
- Pull request — a proposed change submitted for review before merging.
- Nit — a minor, optional suggestion.
- Static analysis — automated checks of code without running it.
- Technical debt — design shortcuts that make future change harder.
- Change failure rate — the share of deployments that cause problems in production.
Frequently asked questions
What should I look for in a code review?
First, correctness: does it do what it should, including edge cases and errors? Then security, design (does it fit the system and stay simple?), tests (do they cover the change?), readability and naming, performance where it matters, and documentation. Leave formatting to automated tools.
How do I give good code review feedback?
Be specific and kind, explain why, suggest an alternative, ask questions when unsure, separate blocking issues from optional suggestions (label nits), and praise good work. Review the code, not the person.
How big should a pull request be?
Small enough to review carefully in one sitting — often a few hundred lines or less, focused on one change. Large pull requests get superficial reviews and hide bugs; split them into reviewable steps.
How fast should code reviews be?
Within a working day is a common goal, and many teams aim for a few hours on the first response. Google's engineering practices recommend responding quickly because slow reviews block teammates and encourage large, risky pull requests.
Are code review skills tested in interviews?
Increasingly, yes — especially for senior and tech lead roles. Some companies give candidates a pull request to review, ask how they handle disagreements in review, or discuss how they've raised code quality on a team.
How does AI change code review?
AI can write and even pre-review code, which increases the volume of code to review and the need for careful human judgement on correctness, security and design. Reviewers must check AI-generated code as rigorously as human code, and AI review tools can help catch simple issues.
Sources
- Google Engineering Practices — How to do a code review
- Google Engineering Practices — Speed of code reviews
- DORA — DevOps Research and Assessment
- SmartBear — Best practices for peer code review
- Stack Overflow — 2025 Developer Survey, AI
- OWASP — Code Review Guide
- AmbitionBox — Software Architect salaries in India (updated 24 Oct 2026)
- Checked October 28, 2026. Figures that change — fees, salaries, prices — are reviewed every six months; if something is out of date, tell us.
Certifications to take next
- 20 AI skills for software engineers — copy-paste prompts for this job, one tap into ChatGPT or Claude
- Code Review and Code Quality Certification — the free 15-minute test on reviewing code, quality and engineering practices
- Git and GitHub skills — the pull-request workflow reviews live in
- AI-assisted development skills — reviewing AI-generated code
- Free skill test · 15 minOpen Source Contribution TestTests the basics of contributing to open source — finding a project and reading its contribution guide, the fork, branch and pull request workflow with Git, writing good issues, commits and PRs, licences and codes of conduct, and working respectfully with maintainers.
- Free skill test · 10 minGit and GitHub Proficiency CertificationTests everyday Git and GitHub — commits, branches, merging and rebasing, resolving conflicts, pull requests and reviews, undoing changes safely and keeping secrets out of history.
- Free skill test · 20 minSoftware Architecture Fundamentals CertificationTests architecture decisions — monoliths vs microservices, quality attributes, scalability, caching, messaging, data consistency, trade-off analysis and documenting decisions.
- Free skill test · 20 minISTQB Foundation Level Practice TestPractice for the ISTQB Certified Tester Foundation Level (CTFL v4.0) — testing fundamentals and the seven principles, testing across the software development lifecycle, static testing and reviews, black-box, white-box and experience-based test techniques, and test management and tools.
- Free skill test · 15 minAI-Assisted Software Development CertificationTests how engineering teams build software with AI — assistants and agents across the SDLC, prompting with context, verifying generated code, security, licensing and measuring impact.
- Free skill test · 15 minAPI Documentation CertificationTests API documentation skills — writing reference docs with the OpenAPI Specification, creating quickstarts, tutorials and guides that improve developer experience, and docs-as-code workflows, style, versioning and maintenance.
Career guides for related roles
- Career guidesAPI design and integration skills for developer jobs in 2027: what interviews test and what good APIs look likeAPI design and integration skills for developer jobs in 2027: resources, errors, pagination, versioning, OAuth, webhooks and idempotency.
- Career guidesTechnical problem-solving interviews in 2027: debugging, estimation and trade-offs — what employers test and how to prepareTechnical problem-solving interviews in 2027: clarifying problems, systematic debugging, estimation and trade-offs, with examples and a plan.
- Career guidesGit and GitHub skills employers expect in 2027: the workflow, interview questions and the profile that gets noticedGit and GitHub skills employers expect in 2027: commits, branching, merge vs rebase, pull requests, undoing mistakes and a profile plan.
- Career guidesAI-assisted software development skills employers want in 2027: verification, specs and working with coding agentsAI-assisted development skills employers want in 2027: coding assistants and agents, verification, specs, security and measuring impact.
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