12 Code Review Best Practices: How to do effective Сode Reviews

Code reviews are crucial to the success of the software development process. They improve the quality of software by catching bugs early and making sure the development teams are always in sync.

Systematic approaches to planning and executing reviews improve their productivity. This, in turn, reduces the waiting periods for deployments and creates better interactions among developers for both senior leaders and junior teams. Even then, many teams still struggle to establish a productive review routine. So, what are the best practices for code review? How can code reviews be efficient and thorough without overwhelming developers?

In this article, we will share DevCom’s 12 best practices for code reviews and the strategies and techniques we apply to have an effective code review.

Before starting the review process, determine the goals of the review itself and what exactly should be achieved. Reviews without a clear purpose are disorganized and even unproductive.

The objectives of the review change depending on how deep it is. Is it focused on coding standards compliance, assessment of security threats or performance enhancement? Getting the development team on the same page from the beginning is crucial.

For example, when reviewing any code block or a code modification that implements payment processing, the primary focus will be on security and error-handling mechanisms. Another review might also focus on refactoring to improve code readability or performance. By setting clear expectations up front, both the developer and the reviewer know what to focus on, which ensures an effective outcome.

One of the most common pitfalls in code review is asking a human reviewer to tackle too much at once. Large reviews often lead to review fatigue and overlooked issues (especially by junior developers). To maintain focus and thoroughness as well as high-quality code, break down larger code changes into smaller, manageable parts.

If a developer has made extensive changes across multiple modules, it’s better to review one module or feature at a time rather than all at once. Smaller reviews allow the reviewer to focus on specific elements, like performance optimizations or proper error handling, without losing sight of important details.

This is a key best practice for code review. Small and frequent reviews are not only easier to manage but also lead to more frequent feedback loops, which accelerate the overall development process.

Code reviews should foster a culture of collaboration and learning. The goal is to improve the code, not criticize the developer. It’s important to maintain a tone of respect and to provide constructive and valuable feedback.

Instead of simply saying, “This is wrong,” consider saying something like, “You could enhance performance by doing XYZ.” Offering solutions rather than solely identifying problems encourages growth and makes the review process collaborative.

Respectful communication is a key element of how to review code successfully and ensures developers remain open to feedback. This constructive approach cultivates a learning and growth atmosphere, which makes teams cohesive and more productive in the long run.

When reviewing blocks of code, look beyond the lines in front of you and consider the broader context. Code doesn’t exist in isolation. It interacts with other systems and components, and the choices made in one section of code can have ripple effects elsewhere in the application.

For example, when reviewing a piece of code related to database queries, consider the overall performance impact. Check if the code introduces potential bottlenecks, if it interacts with external APIs and if timeouts and failures have been handled appropriately. Thinking beyond the immediate code ensures the solution is comprehensive and doesn’t introduce problems elsewhere.

This holistic approach is crucial when considering how to do code review effectively, and it makes sure the code fits smoothly into the broader systems. It also minimizes chances of long-term complications.

Consistency in code style and structure is critical to maintain a codebase that is easy to read and maintain. A major part of reviewing code effectively is ensuring all developers follow agreed-upon coding standards. These could include naming conventions, formatting and structural guidelines that make the code uniform. When reviewing code, look for adherence to these standards.

Questions to be answered at this step:

• Is the variable naming consistent with the project’s conventions?
• Are functions properly structured?

Consistent code reduces confusion and helps onboard new developers quickly. Even the most minor discrepancies add up over time, leading to code that is hard to maintain. Enforcing consistent coding standards is a fundamental code review best practice that ensures long-term codebase health.

One of the primary purposes of a code review is to catch bugs before they escalate into bigger issues. During a review, pay close attention to edge cases that may have been overlooked. Look for potential errors in logic, missed cases in conditionals or improper error handling.

Another area to pay close attention to is security. Code that handles sensitive information, like authentication or payment systems, must be reviewed with extra attention to security flaws like improper input validation or missing encryption. Finding these issues during the review process ensures a stable and secure product down the line, which makes code review effectiveness much higher.

If code is easy to understand, it is also easy to maintain. A key area to focus on during reviews is the structure and readability of the code. Poorly structured code is often the reason for future maintenance problems.

Ask yourself: Would someone be able to look at this piece of code months later and understand why it was written? Would they understand how it is intended to be used? If either answer is “no,” the code might require further development or clarification using comments to improve understanding.

Ensuring code readability by encouraging well formatted, readable code is one of the most important code review practices. Readability becomes more significant in large teams where the same code will be handled by different developers over a period of time. Well written code aids in easier implementation of future changes with little or no chance of new defects being introduced.

Modularity is essential to design extendable software that is easy to maintain. Encouraging developers to write modular code means different sections of the application can function independently, making it easier to test, debug and reuse. When performing code review, think of ways things can be broken into smaller modules, like discussed in best practice number two.

Questions to be answered at this step:

• Are there functions that could be broken into smaller, more focused units?
• Are there pieces of code that are duplicated several times throughout the codebase that can be encapsulated in one reusable header or module?

Highlighting opportunities and making suggestions to create modular or reusable code is an integral part of how to do a code review and do it well. Modular and reusable code not only makes future development easier; it also makes sure the software is able to scale with the development of new features.

Testing is one of the most important practices in software development, and code review is a prime opportunity to ensure code has been properly tested.

During the code review, evaluate if test units and integration tests are sufficient to validate the new functionality added. Check whether there are tests performed on the code that will confirm all edge cases are satisfied. Also check if there are any tests aimed at checking if the new changes will break any existing functionality.

If some code is poorly tested, the reviewer should recommend increasing testing before the work is considered finished. This practice goes a long way in enhancing the quality of the code-updating process, and it minimizes any risks that may come in the future.

Testability has to be similarly considered during reviews because this test-driven code leads to stable software. Also, false bugs can be found early so small issues do not become big problems later on.

Automated code review tools, code analysis tools, code checkers or collaborative code review tools can shorten code review by addressing common problems quickly. Static code reviews include linter tools as well as other static code analyzers for the source code while performing mainly syntax checking along with potential programming defects and deviation from the coding guidelines that do not require, in most cases, manual human effort.

These will perform simple tasks quickly and help experienced reviewers concentrate on logical issues and complex logic architecture decisions and design patterns. Automation tools help maintain a balance between the speed and quality of the code review process.

Adopting automation tools as a component of code quality checks improves productivity and prevents deterioration of code quality during every phase of the development process.

Code reviews should not only focus on lines of code but also on the accompanying documentation. Documentation is crucial to ensure future developers or senior engineers can understand the purpose of the code, how it works and any important implementation details.

Questions to be answered at this step:

• Are there clear comments explaining complex or unobvious parts of the code?
• Is there sufficient high-quality and high-level documentation outlining how the code interacts with other systems or features?

Lack of documentation can lead to later confusion, so it’s important to catch potential issues early. Clear documentation ensures code is easy to understand and maintain, both now and in the future.

Code reviews are not a one-time activity. Code review practices should be constantly evaluated and improved upon as more time passes and more work to accomplish arises. Process reflection involves examining and critiquing one’s thinking relative to employed code review practices.

Questions to be answered at this step:

• Is the review cycle longer than necessary?
• Are typical problems overlooked?
• Do developers appreciate the review or find it unnecessary?

Improving peer code review will improve the efficiency of the process and encourage the incorporation of team members’ ideas. This ensures the review process is efficient, effective and valuable to all. Targeting developing practices to improve and sustain a culture of learning in all aspects of code review will ultimately create better software practices over time.

Now you know how to do a good code review using DevCom’s best practices for code review. This process is not only about finding mistakes; one of the benefits of code reviews is improving the development life cycle as a whole. Adhering to these code review best practices allows for improvement in collaboration and code quality as well as reduction in the chances of similar problems in the future.

Software code reviews are necessary and effective for the successful development of reliable, expandable and easily supported software systems when performed properly by a code author.