8 Code Review Best Practices That Actually Work in 2025

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Code reviews are sucking the life out of your team. No, the answer isn’t to get rid of them.

I know exactly how your code reviews go down, but I’ll say it out loud here just so we’re all on the same page.

Let’s set the scene first. A pull request lands in your queue. It’s massive, touching a dozen files with over a thousand lines changed. The description is a cryptic one-liner: "Fix bug," linking to a Jira ticket you don't have access to. You sigh, knowing this is going to be a multi-hour slog through unfamiliar code, trying to piece together the context from commit messages alone. You finally carve out the time, leaving a few vague comments like "This seems complex" or "Can we simplify this?" because you're too drained to offer more.

Hours later, the author responds, clearly defensive. They've already moved on to another task and now have to context-switch back, decipher your feedback, and push back because they don't understand your concerns. Meanwhile, two other dependent tasks are completely blocked. The whole process feels less like a collaborative quality check and more like a bureaucratic bottleneck.

Why do you even do this anymore? Is it time to just rubber-stamp PRs and let QA sort it out?

Even if it might make sense on the surface to finally pull the trigger and remove this time-suck from your calendar, hopefully, you’re not actually truly considering doing that — because if you are…

You’ve missed the point.

The issue you undoubtedly have with code reviews is how utterly useless they are. The thing is, it can be solved — we just need to think about it through a different lens: usefulness.

We have to get back to the core purpose that a code review is supposed to serve. It’s supposed to be about improving code quality, sharing knowledge, and fostering a sense of shared ownership. In other words, it’s supposed to be about collaboration — not “collaboration” in air quotes, but real, true, honest Collaboration with a capital C. The type of collaboration that stems from trust and leads to alignment. This list of code review best practices will help you ship better products, faster. So, let’s fix it.

1. Keep Code Reviews Small and Focused

When a developer submits a 2,000-line pull request that touches a dozen files, what’s the first thought that goes through a reviewer's mind? It’s probably something along the lines of, "Well, there goes my afternoon." This massive, monolithic review request is a productivity killer and a surefire way to get superficial feedback.

The core principle here is simple: smaller units of change are easier to understand, faster to review, and far more likely to receive high-quality feedback. When a reviewer is faced with a wall of code, their ability to spot subtle logic errors or security vulnerabilities plummets. This isn't just a theory; it's a well-documented phenomenon.

Big tech companies figured this out long ago. A well-known study from a Cisco development team found that developers should review no more than 200 to 400 lines of code at a time. Beyond that, the ability to find defects craters. At a startup I advised, they were celebrating their "high velocity" by merging huge PRs. The problem was, their bug rate was through the roof. After mandating PRs under 300 lines, their bug count dropped by over 60% in one quarter.

This data visualization highlights the optimal conditions for an effective code review.

As the numbers show, sticking to a smaller change size directly correlates with a dramatic increase in defect detection and a more efficient review cycle.

How to Implement Small, Focused Reviews

Breaking down large features isn't always straightforward, but with the right techniques, it becomes a natural part of the development workflow. Here are actionable tips to make this one of the most impactful code review best practices your team adopts:

Use Feature Flags: For large-scale changes, feature flags are your best friend. They allow you to merge incomplete code safely, breaking the feature into smaller, independently reviewable PRs without impacting users.

Stack Dependent Pull Requests: If one piece of work depends on another, create a "stack" of PRs. Submit the base PR first, then create subsequent PRs that build upon it. Tools like Graphite or GitHub’s own stacking features make this much easier to manage.

Embrace Draft PRs: Use draft or work-in-progress (WIP) pull requests to get early feedback on your approach before the code is fully polished. This prevents investing significant time in a direction that might need a course correction.

Establish Clear Team Guidelines: Agree as a team on a maximum line count for PRs (e.g., 400 lines). You can even enforce this with CI/CD checks that flag PRs exceeding the limit. Developing these habits is a key part of staying organized and efficient at work.

2. Use a Code Review Checklist

How many times has a reviewer approved a pull request only for a simple, preventable bug to slip into production? Human memory is fallible, especially under pressure. Relying on each reviewer to recall every single check—from security vulnerabilities to style guide adherence—is a recipe for inconsistency.

A code review checklist formalizes the process, turning it from a subjective art into a repeatable science. It acts as a cognitive safety net, ensuring that critical aspects aren't overlooked. By providing a structured list of items to verify, you standardize quality, reduce the mental load on reviewers, and create a consistent baseline for what constitutes a "good" review.

This isn't about micromanagement; it's about empowerment. The concept was popularized by Atul Gawande's book The Checklist Manifesto, which showed how simple checklists dramatically reduced errors in surgery. The same principle applies to code. Atlassian champions the use of checklists to maintain high standards for readability and maintainability across their massive codebase.

How to Implement a Code Review Checklist

Creating and maintaining an effective checklist is a team effort. It should be a living document that evolves with your projects and challenges. Here are actionable tips for making this one of the most valuable code review best practices your team can adopt:

Start Simple and Iterate: Don't try to build the perfect, all-encompassing checklist on day one. Start with 5-10 critical items based on common bugs or team conventions. Did a recent outage occur due to improper error handling? Add "Are all potential errors gracefully handled?" to the list. The best checklists are forged from real-world production incidents.

Balance Technical and Non-Technical Items: A great checklist covers more than just code logic. Include items for both technical rigor (e.g., "Is there adequate test coverage?") and non-technical quality (e.g., "Is the documentation clear and updated?" or "Are variable names intuitive?").

Automate the Obvious: Your checklist should not include items a machine can check. Use linters, static analysis tools, and code formatters to automatically enforce style guides. Reserve the human reviewer's valuable brainpower for things that require critical thinking, like architectural soundness.

Categorize and Prioritize: Not all checklist items are created equal. Separate your list into "Must-Haves" (blockers for approval) and "Nice-to-Haves" (suggestions for improvement). This helps reviewers focus on what truly matters.

Review the Checklist Regularly: Your checklist should never become stale. Dedicate time in your team retrospectives to review and update it. Remove items that are no longer relevant and add new checks based on recent lessons learned.

3. Provide Constructive and Specific Feedback

Receiving feedback on your code can feel like a personal critique, especially when comments are blunt, vague, or condescending. A comment like "This is wrong, fix it" does more than just miss the mark; it kills morale, creates friction, and transforms a collaborative process into a confrontational one. The goal of a code review isn't to prove who's smartest in the room; it's to collectively improve the codebase.

This is why one of the most crucial code review best practices is mastering the art of constructive feedback. It’s about focusing on the code, not the coder. It involves being specific, explaining your reasoning, and maintaining a respectful, collaborative tone. When done right, feedback becomes a tool for mentorship and team growth.

This principle is more than just being nice; it has tangible benefits. Google’s internal engineering guidelines famously emphasize using "we" over "you" to foster a sense of shared ownership. This simple linguistic shift changes the dynamic from accusatory to collaborative. At a startup I worked with, we saw a noticeable drop in PR revision cycles after we adopted a simple rule: every piece of critical feedback had to be framed as a question.

How to Provide Constructive and Specific Feedback

Transforming feedback from criticism into coaching is a skill that strengthens teams and elevates code quality. Here are actionable tips for making your feedback more effective:

Ask Questions, Don’t Make Demands: Instead of stating something is incorrect, frame it as a question. Rather than "This logic won't handle null values," ask, "What are your thoughts on how this function will behave if this variable is null?" This opens a dialogue instead of shutting it down.

Use Collaborative Language: Frame comments from a team perspective. Swap "You should extract this into a helper function" for "We could probably improve readability by extracting this logic into a helper function." It reinforces that everyone is working toward the same goal.

Acknowledge the Good: Don't just point out flaws. When you see a clever solution, a well-written test, or a clean refactor, call it out. Positive reinforcement is a powerful tool for encouraging best practices.

Provide Rationale and Examples: A comment like "Use a different data structure" is unhelpful. A better comment is, "Have you considered using a Set here instead of an Array? It would provide O(1) lookups and prevent duplicate entries, which might be more efficient. Here’s a link to the docs on it."

Use Comment Prefixes: Standardize comment types to clarify intent. Common prefixes include NIT: (for minor nitpicks), SUGGESTION: (optional improvement), QUESTION: (needs clarification), or BLOCKING: (must be addressed before merge). This helps authors prioritize.

Know When to Talk in Person: If a discussion in the comments thread becomes a novel, it's time to switch to a synchronous conversation. A quick 10-minute huddle can resolve in minutes what might take hours of back-and-forth typing.

4. Automate What Can Be Automated

How many times has a pull request been held up by a debate over trailing whitespace or whether to use single versus double quotes? These conversations are the technical equivalent of arguing about the font on a TPS report; they drain energy and distract from what truly matters. Humans are incredible at solving complex logic problems, but we're expensive, slow, and inconsistent when asked to be syntax police.

The solution is to delegate these mechanical tasks to the machines. By using automated tools for formatting, style enforcement, and basic security scans, you create a consistent quality baseline for every submission. This frees up human reviewers to focus their cognitive energy on higher-level concerns like architectural soundness, business logic, and potential edge cases a machine would miss.

When a linter catches a style issue, it's an impersonal, objective correction. When a human does it, it can feel like personal criticism. Automation depersonalizes the easy stuff. Companies like Airbnb and Shopify have seen massive gains, automatically catching thousands of style issues before a human ever sees the code.

How to Implement Automation in Your Code Review

Integrating automation is one of the highest-leverage code review best practices you can adopt. It’s a force multiplier for your team's efficiency and code quality. Here are actionable steps to get started:

Start with Linters and Formatters: Tools like ESLint and Prettier for JavaScript or Black for Python are easy to implement and offer immediate, high-impact wins. They enforce consistent style and formatting with zero manual effort, ending stylistic debates for good.

Integrate Checks into CI: Don't rely on developers to run tools locally. The most effective approach is to run all automated checks as part of your Continuous Integration (CI) pipeline. A PR that fails a check should be blocked from merging. This is a core tenet of effective CI/CD, which you can learn more about in these continuous integration best practices.

Use Pre-Commit Hooks: For even faster feedback, configure pre-commit hooks that run formatters and linters automatically before a developer can even commit their code. This catches issues at the earliest possible moment.

Add Static Analysis Security Testing (SAST): Incorporate tools that scan for common security vulnerabilities, like SQL injection. Catching these early in the CI pipeline is far cheaper and safer than finding them in production.

Document Your Rules: Don't just turn on a rule; document why it exists. Having a shared understanding of the purpose behind your automated standards helps with team buy-in. Exploring resources on AI prompts in software engineering could also reveal innovative ways to streamline parts of the review process.

5. Review Code Promptly

A pull request (PR) sitting idle is more than just a line item on a Kanban board; it’s a roadblock to progress, a momentum killer, and a quiet drain on team morale. When a developer ships a PR, they’re in a state of peak context. Forcing them to wait days for a review means they’ll have to painstakingly reload all that complex logic back into their brain, costing valuable time and focus.

Timely code reviews are the grease in the gears of a high-velocity engineering team. The core principle is treating review requests with the same urgency as a critical bug. By responding quickly, you prevent context-switching costs for the author, reduce bottlenecks, and foster a culture where unblocking teammates is a shared priority.

Elite-performing teams have weaponized this practice. Shopify famously targets a 4-hour initial response time for reviews, a policy they credit with helping achieve 50% faster feature delivery. Similarly, data from Google’s engineering teams shows that reviews completed within one business day require 40% fewer follow-up revisions. Speed and quality are not mutually exclusive.

How to Implement Prompt Reviews

Making timely reviews a team habit requires shifting the mindset from "I'll get to it when I have time" to "Unblocking others is part of my primary work." Here are actionable tips to make this one of the most impactful code review best practices your team can adopt:

Timebox Your Review Sessions: Don't let review requests constantly interrupt your flow. Block dedicated time in your calendar for code reviews, for instance, a 30-minute block at 10 AM and another at 3 PM. This creates a predictable cadence.

Prioritize Unblocking Others: Adopt a team norm where checking for open review requests is the first thing you do before diving into your own new coding tasks. This "review first" mentality ensures that your teammates' progress is a top priority.

Communicate Delays Proactively: If you're swamped and can't provide a thorough review within a reasonable timeframe (e.g., a business day), don't just leave the author hanging. Acknowledge the request, communicate your timeline, and suggest an alternative reviewer.

Automate and Balance the Load: Use automated systems to distribute review requests fairly. Tools that use a round-robin or load-balancing algorithm prevent any single developer from becoming a bottleneck and ensure review work is shared equitably.

6. Use Pull Request Descriptions and Context

A pull request (PR) with a title like "Fix bug" and an empty description is a silent cry for help. It forces reviewers to become detectives, piecing together clues from file changes to figure out the what, why, and how. This isn't just inefficient; it’s a recipe for missed context and superficial feedback.

The remedy is simple but powerful: treat your PR description as the cover letter for your code. A comprehensive description provides the critical context that transforms a code review from a frustrating chore into a productive discussion. It equips the reviewer with everything they need to understand the problem, evaluate the solution, and test the changes effectively.

This isn't just a nicety; it's a practice institutionalized by high-performing teams. The open-source Rails core team is famous for its exacting standards on commit messages. At a startup I worked at, we had a major production incident because a seemingly innocent change had a subtle side effect. The PR description was empty. After that, we implemented a strict template, and the number of "surprise" bugs dropped significantly.

How to Implement Rich PR Descriptions

Making detailed descriptions a habit requires structure and discipline. By creating a clear template and setting team-wide expectations, you can ensure this crucial context is never skipped. Here are actionable tips to make this one of the most effective code review best practices your team follows:

Implement PR Templates: Don't leave it to chance. Create a markdown template in your repository (e.g., .github/pull_request_template.md) that automatically populates every new PR. This standardizes the required information.

Explain the ‘Why,’ Not Just the ‘What’: The code itself shows what changed. The description must explain why it changed. Was it to fix a customer-reported bug or address a performance bottleneck? Linking to the original ticket provides a clear audit trail. This level of detail is a cornerstone of a well-documented process, much like those found in agile project management with Jira.

Use Visuals for UI Changes: If your PR touches the user interface, a picture is worth a thousand lines of code. Include "before" and "after" screenshots or GIFs to make visual changes immediately obvious.

Guide the Reviewer: Call out specific areas where you are uncertain. Phrases like, "I'm not sure if this is the most performant way to handle this, what do you think?" or "I'd appreciate a close look at the error handling in UserService.ts" direct your reviewer's attention to the most critical parts.

7. Balance Thoroughness with Pragmatism

The pursuit of perfection is a noble goal, but in software development, it can be a silent killer of progress. We’ve all seen a pull request get stuck in review limbo for days, caught in a spiral of ever-more-minor suggestions. The code is functionally sound, but the review becomes an endless debate over variable names or micro-optimizations.

Balancing thoroughness with pragmatism means knowing when to say, "This is good enough to ship." It’s about distinguishing between critical, blocking issues and nice-to-have improvements. This practice doesn't advocate for shipping sloppy code; instead, it promotes iterative improvement and prevents perfectionism from becoming a bottleneck.

This mindset is central to many successful tech cultures. Spotify often frames the merge criteria with a simple question: "Is this better than what we have now?" Similarly, Reid Hoffman, co-founder of LinkedIn, famously said, "If you're not embarrassed by your first release, you released too late." These philosophies underscore the importance of momentum over flawless execution.

How to Implement Pragmatic Reviews

Adopting this balance requires a conscious shift in team culture. Here are actionable tips to make this one of the most effective code review best practices your team can adopt:

Use Clear Comment Labels: Introduce a simple prefix system for feedback to clarify severity:

BLOCKING: Must be fixed before merge (e.g., a bug or security flaw).
SUGGESTION: A non-blocking idea for improvement that can be addressed now or later.
nit: (short for nitpick) For minor style preferences that don't block the merge.

Ask the Right Questions: Before blocking a PR, reviewers should ask themselves, "Does this change prevent the code from working correctly, introduce a security risk, or create a significant performance problem?" If the answer is no, consider whether the feedback can be a follow-up ticket.

Create Follow-Up Tickets: For non-critical improvements discovered during a review, the best path forward is often to create a new ticket. This unblocks the current PR and ensures the suggestion isn't forgotten.

Establish Team Guidelines: Agree on what constitutes a blocking issue. Document these standards and make them part of your team's onboarding process. For complex projects, like those requiring specialized Ruby on Rails upgrade services, this balance is crucial. This approach aligns well with many of the core tenets found in agile development best practices.

When you think of a code review, "quality gate" is probably the first phrase that comes to mind. While that's true, seeing it only as a gatekeeping activity is a massive missed opportunity for your team's growth.

Code review is one of the most powerful, built-in learning mechanisms a software team has. It's a forum for mentorship, a library of practical examples, and a catalyst for spreading knowledge across the codebase. This transforms the review process from a transactional quality check into a collaborative experience that elevates the collective skill set of the entire team.

This idea is deeply rooted in practices like Extreme Programming's principle of collective code ownership. Companies that excel at this see reviews as a two-way street. Stripe encourages developers to add "TIL" (Today I Learned) comments in reviews to highlight new discoveries. At Khan Academy, reviewers are sometimes rotated across teams specifically to cross-pollinate knowledge. This shift in mindset fosters a culture where asking questions is not a sign of weakness but a mark of engagement.

Making code reviews a learning opportunity requires intentional effort. Here are actionable tips to weave this practice into your team's DNA, turning it into one of your most valuable code review best practices:

Explain the "Why": When suggesting a change, don't just say what to change; explain why. Link to documentation or relevant articles. Instead of "Use a Set here," try "A Set would be more efficient here because it offers constant-time lookups. Here's a quick read on it."

Rotate Reviewers Strategically: Avoid having the same senior engineer review all the code for a specific component. Intentionally assign reviewers who are less familiar with that part of the codebase. This spreads domain knowledge and prevents knowledge silos.

Encourage Junior-on-Senior Reviews: Have junior developers review code from senior developers. This is an incredible learning tool, allowing them to see expert-level patterns and ask clarifying questions in a low-pressure environment. It demystifies complex code and accelerates their growth.

Establish a "Learning Channel": Create a dedicated Slack channel or a shared document where team members can post interesting snippets or insights discovered during code reviews. This captures valuable lessons that might otherwise be lost. By centralizing these insights, you can dramatically improve team productivity and build a shared knowledge base.

8 Best Practices Comparison Guide

Practice	🔄 Implementation Complexity	💡 Resource Requirements	📊 Expected Outcomes	⭐ Key Advantages	⚡ Ideal Use Cases
Keep Code Reviews Small and Focused	Moderate (planning to split features)	Medium (multiple PRs, tool support)	Higher defect detection (70-90% better), faster feedback	Deeper focus, reduced reviewer fatigue, faster turnaround	Teams emphasizing quality and fast iteration
Use a Code Review Checklist	Low to Moderate (create and maintain)	Low to Medium (documentation, training)	Consistent reviews, fewer oversights	Standardizes quality, accelerates onboarding	Teams needing consistency and reducing missed issues
Provide Constructive and Specific Feedback	Moderate (skill and discipline needed)	Medium (time and communication skills)	Improved team culture, better quality discussions	Builds trust, accelerates learning, reduces conflict	Teams focused on collaboration and growth mindset
Automate What Can Be Automated	Moderate to High (setup and maintenance)	Medium to High (tools, CI/CD integration)	Instant mechanical issue detection, consistent style	Frees reviewers, scales with team size	Teams wanting efficiency and to reduce manual work
Review Code Promptly	Low to Moderate (team discipline)	Low (time management)	Maintained momentum, fewer bottlenecks	Keeps flow, improves delivery speed	Fast-paced teams or with high review volume
Use Pull Request Descriptions and Context	Low (templates and discipline)	Low (time to write)	Reduced confusion, faster reviews	Improves communication, aids future debugging	Any team aiming to improve review efficiency
Balance Thoroughness with Pragmatism	Moderate (judgment in prioritization)	Low to Medium (guidance and training)	Avoids paralysis, maintains velocity	Focuses on high-impact issues, reduces friction	Teams balancing quality with delivery speed
Encourage Knowledge Sharing and Learning	Moderate to High (cultural shift)	Medium (time, teaching skills)	Enhanced skills, shared knowledge, stronger team	Builds cohesion, spreads expertise, makes reviews valuable	Teams investing in continuous learning and growth

Now Go Capitalize on Collaboration

We’ve navigated the landscape of code review best practices, from keeping pull requests small to fostering a culture of learning. It’s easy to look at a list like this and feel a bit overwhelmed. You might be thinking, "This all sounds great, but where do I even start?"

If that’s you, I get it. The friction you feel in your current review process isn’t a sign of failure. People care enough about your product to feel that it’s worthwhile to fight to make it better. That is an incredibly positive takeaway. Instead of letting it fester into resentment, it’s time to alchemize that weighty lead of bitterness into product gold. You’re in a privileged position to transform what is often a dreaded chore into one of your team's most powerful rituals for shipping high-quality software and mentoring engineers.

Turning Theory into Reality

Mastering these code review best practices is less about memorizing a checklist and more about cultivating a mindset. It's about shifting the goal from "finding mistakes" to "collecting perspectives." The true value isn’t just catching a bug; it’s the conversation that prevents a dozen similar bugs from ever being written. It’s the senior engineer sharing a design pattern that unlocks a junior developer’s potential.

The core themes weaving through every practice we discussed are clarity, communication, and consistency.

Clarity: Small PRs with detailed descriptions remove ambiguity. A clear checklist ensures everyone is evaluating against the same standards.

Communication: Reviews are a dialogue, not a monologue. The process is a chance to ask questions, share context, and align on the "why" behind the "what."

Consistency: Automation ensures rules are applied evenly. Prompt reviews prevent bottlenecks and keep the development engine humming.

But just like any other agile ceremony, from standups to retros, the process itself requires management. If your team spends its days juggling GitHub notifications, digging through Jira, and manually pinging reviewers on Slack, you’re paying a heavy tax on focus and flow state. The cognitive overhead of managing the process of code review can easily negate the benefits. You're trying to move fast, but the administrative drag is forcing you to move fast with broken infrastructure.

This is where the right tooling becomes a force multiplier, turning abstract ideals into your team’s daily reality. Take these practices, pick one or two to start with, and open a conversation with your team. Build a review culture that doesn’t just catch errors but actively elevates the entire team.

Ready to eliminate the administrative overhead from your code review process? Momentum integrates with your existing tools like Jira and GitHub to connect PRs with their underlying tickets, automate status updates, and provide the visibility needed to keep reviews flowing smoothly. See how you can implement these best practices and get back to building great software by trying Momentum today.