Beginner
6 min read
Updated January 2025
Getting Started with Code Review
Learn the fundamentals of code review and how to implement an effective review process for your team. Perfect for developers new to code review or teams starting fresh.
What is Code Review?
Code review is when other developers examine your code changes before they become part of the main codebase. Think of it like having a colleague proofread an important email before you send it.
Simple Example
You write code:
def calculate_total(items):
total = 0
for item in items:
total += item.price
return total
Teammate reviews and suggests:
"Good logic! Consider adding a check for empty items list and handling items that might not have a price."
You improve the code:
def calculate_total(items):
if not items:
return 0
total = 0
for item in items:
if hasattr(item, 'price') and item.price:
total += item.price
return total
Why Code Review Matters
Catch Bugs Early
Four eyes are better than two. Reviewers often spot issues the author missed.
for i in range(len(users) + 1): # Bug: off-by-one error
Reviewer: "This will cause an index error. Should be range(len(users))"
Learn and Teach
Junior developers learn from seniors. Seniors discover new approaches from juniors.
"Great solution! I didn't know about the collections.Counter class. Much cleaner than my loop approach."
Maintain Standards
Keep codebase consistent and follow team conventions.
"We use camelCase for variables in this project. Could you rename user_data to userData?"
Share Knowledge
Multiple people understand each part of the codebase.
"This payment processing logic is complex. Could you add some comments explaining the flow?"
Setting Up Your First Code Review Process
1Choose Your Platform
GitHub
• Pull Requests
• Inline comments
• Required reviewers
• Most popular choice
GitLab
• Merge Requests
• Approval rules
• Code quality reports
• Built-in CI/CD
Bitbucket
• Pull Requests
• Atlassian integration
• Branch permissions
• Jira integration
2Configure Branch Protection
On GitHub, go to Settings → Branches → Add rule:
✅ Require a pull request before merging
✅ Require review from code owners
✅ Dismiss stale reviews when new commits are pushed
✅ Require status checks to pass before merging
This prevents anyone from pushing directly to your main branch without a review.
3Set Team Guidelines
Basic Team Agreement
All code must be reviewed before merging
Keep pull requests under 400 lines when possible
Review within 24 hours (48 hours for large PRs)
Be kind and constructive in feedback
Include tests with new features
How to Do Your First Code Review
Review Checklist for Beginners
📖 Start Here
🔍 Look For
What to Focus on as a New Reviewer
✅ Do Focus On
- • Logic errors and bugs
- • Missing error handling
- • Code that's hard to understand
- • Potential security issues
- • Whether tests cover the changes
❌ Don't Worry About
- • Minor style issues (spaces, etc.)
- • Variable naming preferences
- • Architecture decisions (for now)
- • Performance micro-optimizations
- • Rewriting in your preferred style
How to Give Good Feedback
❌ Poor Feedback
"This is wrong"
"Bad code"
"Fix this"
"I don't like this"
Vague, unhelpful, no suggestions
✅ Good Feedback
"This function doesn't handle the case when user is None"
"Consider adding input validation here"
"This could throw an exception if the list is empty"
"Great approach! One suggestion..."
Specific, helpful, constructive
Common Beginner Mistakes
Nitpicking on Style
Problem:
Focusing on spaces, brackets, and formatting instead of logic
Solution:
Use automated formatters (Prettier, Black) to handle style automatically
Example:
Don't comment on: 'Use single quotes instead of double quotes'
Being Too Nice
Problem:
Approving everything to avoid conflict or hurt feelings
Solution:
Remember: catching bugs early helps everyone. Be kind but thorough
Example:
It's better to catch a bug in review than in production
Overwhelming with Comments
Problem:
Commenting on every line and overwhelming the author
Solution:
Focus on the most important issues first. You can always do follow-up reviews
Example:
Pick 3-5 significant issues rather than 20 minor ones
Taking Too Long
Problem:
Spending days on a review because you want it to be perfect
Solution:
Start with a time limit (30 minutes for small PRs, 1 hour for large ones)
Example:
Better to give quick, useful feedback than perfect, late feedback
