Code review: what to look for and how to write review comments
For anyone who reviews or submits changes to code, scripts or infrastructure definitions: developers, automation engineers and senior technicians. You should be able to read code in at least one language and have used pull requests or merge requests. Based on Google's published engineering practices: the standard for approving a change, what to check and in what order, how fast to respond, how to write comments that are kind and actionable, how to handle pushback, and how to write a change description reviewers can work with.
- Level
- Intermediate
- Length
- About 70 minutes
- Contents
- 5 lessons · final exam
- Status
- Published · updated 10 Oct 2026
Skills you'll practise
- Decide whether to approve a change using the 'improves overall code health' standard
- Identify design, functionality, test, naming and comment problems in a change
- Write review comments that explain why, focus on the code and label their severity
- Choose how to respond when an author pushes back or offers to clean up later
- Write a change description with an imperative summary line and a body that explains what and why
Course outline
- 1.What a review is for, and when to approveLesson · 14 min
- 2.What to look for, and in what orderLesson · 18 min
- 3.Writing review comments that explain why and label severityLesson · 11 min
- 4.Responding when an author pushes back or offers to clean up laterLesson · 6 min
- 5.Being reviewed: descriptions and reviewable changesLesson · 12 min
- 6.Code review: what to look for and how to write review comments: knowledge checkKnowledge check · 14 questions
- 7.Code review: what to look for and how to write review comments: practical exerciseKnowledge check · 1 question
- 8.Final exam10 questions · passing it completes the course, so people who already know the material can test out
Sources it draws on
The lessons and questions are written from these references, so learners can go back to the original.
- Google Engineering Practices Documentation (terminology and CC BY 3.0 terms)
- Google Engineering Practices: The Standard of Code Review
- Google Engineering Practices: What to look for in a code review
- Google Engineering Practices: Navigating a CL in review
- Google Engineering Practices: Speed of Code Reviews
- Google Engineering Practices: How to write code review comments
- Google Engineering Practices: Handling pushback in code reviews
- Google Engineering Practices: Writing good CL descriptions
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