8 Free/Open Source Code Review Tools for 2020


Sharad Bhardwaj

Senior editor

Parul Saxena

Chief editor

Last updated: June 17, 2020

Code review is an integral part of the development process. It is used to find out bugs and errors at an early stage of development itself. 

The code review tools are so designed that it automates the whole process of reviewing the application development process. Thus, it has become an important tool for the development team. 

This code review process helps improve the quality of the software. To help you out, we have listed out the top eight free and open-source code review tools that you might want to take a look at.

What is the Code Review Process?

The code review process is orderly testing of software to find and remove errors, bugs, buffer overflows, and other vulnerabilities found in the codes.

These code review processes are methodically documented and follow severe defect detection techniques from peers and technical experts. There are basically four, sometimes five participants who are involved in code creation and code inspection – the author, the moderator, the reviewer, the reader, and sometimes an observant.

The code reviews are led by trained moderators and reviewers who are NOT the author of the coded program, and these reviews are performed without any management participation.

Since it is a quality assurance activity, reviewers scrutinize the codes written by the authors and prepare a report with a list of findings to be fixed.

How to perform a code review?

There are many processes and techniques to perform a code review which usually involves a lot of meetings between the distinct roles mentioned above. 

There are heavyweight inspection processes that go up to 6-7 steps involving everyone to work only when the code review comes on their plate and there are lightweight inspection processes that involve everyone to work simultaneously with each other.

Not many follow heavyweight inspection processes anymore, which means lightweight processes are trending more with the increase in the development of software applications across the globe.

Here are a few lightweight inspection techniques:

  • Over-the-shoulder reviews

This code review process is the most informal and common. Over-the-shoulder means that a reviewer hovers over the author while the author displays the changes made in the code at their coding workstation.

The author is the person that leads the code review by sitting at their computer, explaining the changes he/she made in the code while going through multiple tools and files in the project.

If the reviewer finds any discrepancy, then they engage on the spot with the author (this engagement is called pair-programming) to fix the missed issues. If the changes are too significant, then the entire live code is taken off-line.

However, with modern desktop-sharing tools, this “over-the-shoulder” review has become remote and easy to implement over long distances.

  • Email pass-around reviews

This process of code review is prevalent and preferred by most open-source projects. Here, the entire file or changes in the code are packed up by the author and sent to the reviewers through email. Reviewers then examine the code data, ask relevant doubts and queries in the same thread to the authors.

In this method, it is easier to involve other developers through the email itself to ask for suggestions, changes in the code, expert advice, or even complete deferral.

  • Pair programming reviews

People generally associate this technique of code review with Extreme Programming (XP) because it incorporates a continuous code analysis. In pair-programming, two developers produce code from a single workstation, with only one authoring the code and the other person freely discussing any changes and suggestions needed as a reviewing developer.

Pair-programming has shown to be very useful in finding bugs as well as promoting knowledge transfer. 

However, this process poses a controversial issue about whether it is better or worse or equivalent to more standard reviewing methods because the reviewing developer is continually being a critique polishing the code. 

At the same time, the author might get frustrated and keep losing his/her chain of programming the code every time in between writing and listening for suggestions.

  • Tool-assisted reviews

A code review done with the help of specialized tools that helps in processes like collecting files, commentary, transfer, and displaying data, collecting metrics, etc., is called a tool-assisted review.

Tool-assisted reviews can allow product managers and administrators to exercise some control over the workflow. Such type of review process is mostly preferred in commercial software, open-source projects, or home-grown scripts.

Either way, it requires a lot of money to be invested in specialized tools to create a better code review environment.

These code review processes help improve the quality of the software. To help you out, we have listed out the top eight free and open-source code review tools that you might want to take a look at.

Best Free and Open Source Code Review Tools to Consider

Software 1: Codebrag

Codebrag is one of the best open-source code review tools that are quite simple to use. It is mainly used to review inline comments and likes, smart email notifications, non-blocking code, and more. 

It is a light-weight review tool that makes the whole process of review entertaining and structured. Furthermore, it offers an agile code review that helps deliver a high-quality application. 

codebrag dashboard


  • Lets you easily track your tasks with a simple to‑do list
  • Offers full IDE integration and also allows it to be installed locally
  • Easily manage all comments and commits in one place


  • Perfect keyboard navigation
  • Easy to install


  • No syntax highlight

Software 2: Gerrit

Gerrit is another free and open-source code review tool that can help you review code on a web browser. It is a self-hosted and light-weight solution. It enables all the committers on a project to keep track of all the changes made. 

The most significant advantage is that it gives you the chance to review the changes before accepting the codebase. Besides, the change facilitator can open conversations about the changes by leaving comments and notes. 

EGerrit Dashboard


  • Can be integrated with Git — a distributed Version Control System
  • Can use it to discuss a few detailed segments of the code
  • Offers repository management for Git


  • Easy to fix compilation errors
  • You can manage version history for future references
  • Fine-grained access control
  • Has 2-level gates to give a green signal to the code


  • Works only with Git
  • Slower than other collaborating tools
  • UI is very native
  • Takes time to get hold of the software by the developers

Software 3: Reviewable

Reviewable is one of the best open-source code review tools in terms of both functionality and appearance. It offers a clean and interactive UI that enables you to perform advanced functionality with ease. Using the device, you can perform actions like comparing the diffs of any two revisions of a file or installing customizable logic that enables you to know if the review of code is complete or not. 

Reviewable dashboard


  • Enables seamless integration and minimal admin work
  • Improves the code quality by highlighting the syntax
  • Lets you map line comments across file revisions and stays in place until it is resolved


  • Batch commenting is possible
  • Easy incremental reviewing
  • Language agnostic
  • Made on modern UI elements


  • Integrates with only GitHub
  • Doesn’t have a simple interface
  • Houses some unnecessary functionalities

Software 4: ReviewBoard

ReviewBoard is a simple yet powerful free code review tool that makes the whole process of reviewing thoroughly. It provides functionalities like diff and the ability to make comments. 

Besides, it is relatively easy- and- quick to learn and provides a clean interface. ReviewBoard is the best option for developers who are looking for a no-frills code review. It has 1.2K GitHub stars and 369 GitHub forks.

review board dashboard


  • Provides syntax highlight that makes it highly readable
  • Supports pre-commit and post-commit reviews
  • Seamlessly integrates with ClearCase, CVS, Perforce, Plastic, and more


  • Self-hosted
  • Unified review queue with detailed information
  • Reviews are composed of multiple comments, not just one
  • Extensive remote API


  • Might increase manual steps to your workflow
  • Not a part of the mainstream GitHub workflow
  • Emails formatting is complicated

Software 5: Phabricator Differential (Open Source)

Phabricator Differential is a free code review tool that enables you to download and install it on your own hardware or launch a hosted instance with them. It is considered the best code review tool amongst the top open-source code review tool. 

What’s more, you can use it HG, Git, and SVN. And if that wasn’t enough, this free code review tool also allows for easy team discussion, planning, testing, and coding. The plus point is that it is scalable to multiple servers. 

Phabricator dashboard


  • Enables developers to leave comments and notes
  • Allows you to publish all repositories to mirrors
  • Easily host the repository locally


  • Powerful and fast
  • Highly scalable


  • Interface is clumsy

Software 6: Rhodecode

Rhodecode is a popular open-source code review tool that makes it easy to handle code management. It is well protected, enterprise source code management system that serves as an integrated tool for Mercurial, Git, and Subversion. 

It offers two editions. The first one is licensed per user named Enterprise Edition, and the other is Community Edition — a free and open-source version. 

RhodeCode dashboard


  • Automates the workflow for faster collaboration
  • Allows for team collaboration for better code quality check
  • Enables you to integrate with the existing code base with new issue tracker tools


  • A secure code review tool
  • Centralized user management
  • Support 3 major version control systems: Mercurial, Git & Subversion
  • Open-source and highly secure
  • Online editing with preview


  • Hard to maintain

Software 7: CodeStriker

The last on our list is Codestriker, which is an open-source code review tool. Using the device, you can easily record issues, leave comments, and notes in a database. It supports reviews of traditional documents and diffs generated by an SCM system and plain unidiff patches. There is a plug-in architecture for supporting issue tracking systems.

What’s more, it minimizes paperwork and provides a clean interface for performing code inspections.

CodeStriker dashboard


  • Can be easily integrated with Bugzilla, CVS, ClearCase, etc.
  • Enables you to record code inspection metrics as a part of the process
  • Runs on all of the important platforms and browsers


  • Easy integration
  • Highly-configurable metrics subsystem


  • Not much used or talked about
  • Complex interface

Software 8: SmartBear

SmartBear has automated software, Collaborator, to help you with your code quality instantly. It supports most of the version control systems like Subversion, CVS, TFS, Perforce, and Git. 

This Smartbear’s software allows reporting and analysis of key metrics along with reviewing design documents related to your code review process. With SmartBear, you can reduce your rework and get answers quickly.

SmartBear dashboard


  • Track and manage defects
  • Build custom review templates
  • Collaborate on documents and software artifacts
  • Improve processes with reporting
  • Integrates with most of the version control systems
  • Save reviews to a Zip file


  • Takes less than a day to set up the software
  • The administration panel is easy to navigate


  • The reporting feature seems canned
  • Customizing a report is complex


So, these were the top 8 open-source code review tools from us which are mostly used by developers all across the globe.

Which one have you so far been working within your company? Tell us your review in the comment section below.

Sharad Bhardwaj is a content analyst at SoftwareSuggest. He loves to advise and help people. In leisure time he likes to be involved in sports activities and listening to music.

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