What is code review?

Code review is a process of examining software in order to assess and determine the source code quality. It is outsourced to an independent third party, as opposed to peer review, which is done within a single team of developers.\

The goal of code review is twofold:

  1. measuring technical debt in the software,
  3. offering solutions to potential problems.

The procedure is comprehensive. The developers take a close look at your software and manually check if your code is:

  • Compatible

Does it work well with other products?

  • Maintainable

How easy is it to fix bugs and implement modifications?

  • Modular

Are the individual components independent and self-sufficient?

  • Robust

Can it withstand significant strain and tolerate unpredictable or invalid input?

  • Secure

Does it hold its own against hostile actions and influence?

  • Efficient

What is the response and reaction time?

  • Scalable

How well does it adapt to an increase in data or the number of users?

What is the code review process?

The process of code review begins by finding a business partner to check the quality of your code.

Step #1: Signing the NDA

Before any work on the software is done, you will be asked to sign what is known as an NDA—a non-disclosure agreement. It is common practice, done to establish trust between the two parties, and serves your best interests. Signing the NDA means the service provider can’t use your software for their own purposes; the code remains your property,  but you give them permission to get familiar with it.

Step #2: Reviewing your code quality

Once you sign the NDA and hand the code over, one or two developers spend a certain amount of time—usually several days—getting acquainted with it, using it extensively, seeing what works and what doesn’t. Two developers are necessary if the amount of frontend is considerable, but if there isn’t too much software to review, one developer well-versed both in frontend and backend will suffice.

Step #3: Comparing your code to “perfect” code

Next, the reviewing party compares your code to a “perfect” model of the code and establishes the differences between the two, grouping and listing them in a clear manner. This provides you with a detailed overview of potentially problematic aspects of your code, including, among many others: code coverage and clustering, file length and structure, and adherence to standards.

Popular code review tools

Developers use a wide range of tools to locate the areas in need of fixing within your software:


Used for static analysis of the source code, linters serve as primary indicators of potential issues with the code. PyLint is a popular choice for Python, while ESLint is used for JavaScript.


This tool measures code coverage, showing the parts of the source code tested for errors. Ideally, 100% of the code is checked, but 80-90% is a healthy percentage.


A more sophisticated analysis tool than the ones used in the first two steps, SonarQube digs deeper into the code and examines several metrics of code complexity. This allows the developers to understand your software better.

It’s worth noting that code review is not about giving the client whatever results these tools come up with. Instead, the results are supposed to help the reviewing team analyze the troublesome areas and use their expertise to evaluate the warnings and their validity.

Code review report and what to do with it

The process of code review ends with the service provider:

  • listing various suggestions for changes,
  • pointing to the steps that need to be taken in order to best improve the code,
  • assessing the time required to bring the software in its current stage to a state as near perfection as possible.

With this final report in hand, you have two options:

  1. go back to the original developer of the code and work with them to improve it,
  3. hire the company that did the code review for you to upgrade your product and continue working on it in the future.

Naturally, you may choose to use the code review to better your service yourself, but it’s not advised. It will cost you a great deal of time and money, and it’s best if the developers doing this are skilled and experienced. Bearing that in mind, outsourcing really is the way to go.

What are the benefits of code review?

The greatest benefits of code review boil down to quality, time, and money.

1. Quality

Code review gives you a unique opportunity to understand your software’s quality and become aware of every area in need of refactoring. As an added bonus, the people doing this are impartial experts.

How well the code is written determines how easy it’s going to be for you to keep growing and developing it. High code quality means working with the existing software and adding new features to it will be smooth and problem-free.

2. Time

As your business grows, so will your team.

If your code is built on the right foundations and follows the proper standards, it will be easier and faster for fresh developers coming onboard to familiarize themselves with your software and work on it effectively.

In addition, if your code quality is low, you will waste precious time navigating through it, finding issues with it and fixing them, or even rewriting the whole thing altogether.

3. Money

An in-depth analysis of your code gives you an exact idea about your software’s current state and how costly it will be for you to improve it.

It’s certainly an investment, but worth every penny. In the long run, high code quality will make maintaining and expanding your service cheaper and more manageable.

What are the drawbacks of code review?

You know that old saying, “If it seems too good to be true, it probably is”? Well, code review is an exception to this rule—it would be a serious challenge to justify not doing it—with one tiny catch.

It can get pretty expensive.

Reviewing code quality, not to mention reviewing it well, requires the expertise of a professional developer or two. Unfortunately, that is not a cheap service.

However, if I told you there are companies who offer this valuable service for free—would that be of interest to you?

The takeaway for you

There’s no better way to say this: code review is essential for making sure your code, and as a result your product, are of the highest quality possible.

Outside help of experienced professionals can be a make-it-or-break-it factor in the success or failure of your service. Even if you have to spend a little for this service, the pros of doing it far outweigh the cons.

So go ahead and do yourself and your code a favor—choose code review.

Also, if you’re not currently in a position to invest in the service—don’t worry. STX Next offers free code review for a limited time. Check it out if you like!