Codacy : An Easy-to Use Code Quality Review Solution

Some time ago, I organized a talk on “Code Quality and why developers should care about” for my company. In that presentation, I demonstrate some tools, unfamiliar for the audience : young developers and battle-hardened IT developers. One among these tools has brought to me a lot of questions : Codacy. I will present its features and perform a comparison between Codacy and SonarQube from SonarSource.

How the choice of a Application Quality Measurement solution is influencing the software team work ?

Disclaimer : this article is not endorsed by Codacy. It reflects my personal opinion and experience.

According to a study ordered by Codacy, Codacy’s product may improve the code quality perception up to 20% and optimize the code review process up to 30%. We can assume that it reflects the disruption brought by the new code quality solutions in contrast with the traditional ones. The power of the code analysis also seems to be a minor criteria in the choice of a solution. Interviewed users are justifying the ROI of such solution in its ability to ease and optimize the software development process.

Codacy is a company started out as Qamine with funding from Seedcamp in 2012. Its clients include Adobe, Deliveroo and Cancer Research UK. more than 30.000 developers are daily using their products and more than 1000 companies use their services. It’s more than a billion of lines of code that are analyzed per day.


Here are the Codacy’s main features :

  • Code review automation
  • Code Quality analytics
  • Engineering Analytics
  • Security Code analysis
  • Cluster installation / multiple instances

The first time, I have tried Codacy, I signed in using my GitHub account and launched some analysis on my public repositories.

On a first glance, we can observe that most of my repositories are analyzed without a line of configuration. Codacy is detecting most of what it needs automatically : handy.

One of my project has not been analyzed. This project is developed in Groovy using a gradle packaging script.

Officially, the supported languages in Codacy are :

  • Scala
  • Java
  • JavaScript
  • Python
  • Ruby
  • PHP
  • Apex
  • JSP
  • XML
  • Velocity
  • VisualForce
  • C#

According to Codacy, the language support can be extended with community plugins :

  • CoffeeScript
  • CSS
  • C/C++
  • Dockerfile
  • SASS
  • Shell Script
  • Swift
  • TypeScript
  • LESS
  • Go


For each one of my projects, Codacy is providing metrics on the quality of my project.

One of the best Codacy’s feature is the “per-commit strategy”. Codacy is triggering an analysis for every commit of my repository. It is even analyzing the past commits of my repository to draw the whole tendency. For each commit, we can see the evolution of the quality : number of created / deleted issues…

The dashboard is clean and really easy-to-use. The widgets provide the necessary information to assess the present project quality. Both metric and violation statistics are integrated in Codacy’s to build a simple qualimetry model (Complexity, Style, Compatibility, Error Prone, Performance, Security, Unused code).

This qualimetry model is specific to Codacy even though it is close enough from the ISO 250001/9126 specification. Codacy does not seem to offer any SQALE / ISO or Security standard models.

A specific dashboard in Codacy allows the developers to evaluate the security characteristic of my project.

Codacy is strongly mapped to your repository and your files. Most of the metrics and violations are associated to your files like on this screenshot. Abstract representations such like packages, modules, namespaces are not represented and the analysis tends to me difficult for large projects

Each information is clearly reported and each file receives a score based on a letter from A to E.

A nice feature in Codacy is that duplicate code is easy to track and to follow like in this screenshot :

An important feature in Codacy is the possibility to handle natively branches, tags and other important things provided by your SCM. It won’t be necessary to create several projects for handling the branches or to imagine tricky project naming.

Codacy can be used as an efficient quality gate to accept / deny your team commits or other external contributions. It becomes very handy with the mechanism of triggers that controls the code quality when the push has been submitted.

Whether you are using Github or your own repository, Codacy provides some integration to perform a priori checks of your commits, pull-requests.

We also find in Codacy, an interface to manipulate and configure the rules used to analyze your code source. However, the functionality is missing of flexibility (Parameters seems to be missing from rules) and the rule documentation has not been imported from the 3rd addons.

After using Codacy deeper, I think that their developers are recommending to include your configuration files directly in your GIT repository.
The configuration can be easily tracked thanks to the versioning of your configuration (and as bonus to be shared with your IDE.)

SonarQube vs Codacy : an alternative ?

I am a frequent user of SonarQube and for that reason, I wish to share my personal comparison between the two solutions to help anyone that could hesitate for another solution.

Engineering analytics

During a long time, SonarQube has been the easiest way to perform code quality analyses. Some years ago — an eternity in this domain -, tools like Squale were requiring a long and difficult process to tune, configure and finally obtain the code metrics. SonarQube brought a new model, “code analysis as a service” where all details from the project creation could be either imported from build scripts like Maven or modified a posteriori. This feature has been the great force of SonarQube.

However, this approach also contains a major drawback. SonarQube is lacking of adaptability to be used as quality gate. An example ? The possibility exists to use SonarQube to perform analyses per commit. It’s a clever trick using your CI Build like Jenkins. However SonarQube won’t hold any metrics per commit, tags, branches. Branches are a rather new feature in SonarQube tough its usage is quite cumbersome, even more to perform the comparison between branches (link1, link2). At the end, technologies like GIT or Bitbucket have created the need for tools that produces metrics for each branch, commit, pull-requests to help the Product Owner.

Security code analysis

Security and vulnerability detection is a tough problem to solve by static analysis tools. This niche market is already populated of well-established leaders (Coverity, Fortify, Klocwork…) These kind of tools are really difficult to implement : misprediction, lack of inform ation and the complexity to understand and to fix the issues are common issues.

Codacy does not improve that domain by providing new tools. It is basically offering a diagnostic based on its results. The diagnostic is built with the data from the plugins and other integrated tools inside Codacy.

Language coverage and the power of the static analyses

At the first glance, the coverage by Codacy is quite impressive. Codacy is well integrated with many open-source tools.

SonarQube is beating Codacy by offering to companies several language supports for proprietary / specialized languages like Cobol, ABAP.

That is a crucial difference between the two solutions. If you are developing legacy software or vendor-locked languages, Codacy is probably not your solution. If you want an application portfolio analysis that offers you a score whatever the languages presents in your code, SonarQube will be the best at this task.

However, if you are developing new software with trendy languages (TypeScript, Scala), Codacy is fitting better. Even if SonarQube is developing their own code analyzers, usually more powerful than the opensource alternative, the consequence is that SonarQube is less reactive to the new languages and frameworks. Several open-source plugins may complete the SonarQube possibilities but it requires that your administrators allow it. That’s the main restriction that prevents some SonarQube users to be able to analysis their new projects.

User friendliness

Along the SonarQube releases, the UX has greatly evolved from an simple but efficient GUI to a highly customisable product allowing Software Quality managers to build their own dashboards.

Although the usage of SonarQube becomes more complex in the recent releases (6) : complexity to obtain the full list of violations, to browse the list of rules violated. These are some use cases difficult to reproduce without using the REST API. SonarQube is in a full transition that deteriorates lightly the user experience.

In contrast Codacy has been designed as a simple but efficient UI to see your data, your indicators simply. It’s easy-to use by a developer team, in a agile context that does not want to spend several hours to align two widgets.


SonarQube or Codacy ? I think both are answering two different usages and expectations.

SonarQube (at least until its Cloud based offer becomes mature) has been an on-premise solution, giving the power to companies to analysis their projects, whatever their organization could be. SonarSource has developed proprietary code analyzers to extend the possibility of their platform to better fulfill their customer needs : security, vendor languages, qualimetry models… The strengths of SonarQube are : proprietary languages support, market leadership, open-source / proprietary licensing model. Its weaknesses are an expensive/ slightly complex licensing model, an complex UI, an on-premise solution and possibly a lack of responsiveness to the market needs.

Codacy in comparison has been designed as a Cloud-based solution thought to fit the needs of remote software developers, using mainly Github, Bitbucket Saas service, working, building, communicating and deploying into the Cloud. Their solution is deeply mapped to the organization of your code repositories.

Codacy’s strengths are : easy to use, a friendly UI, the possibility to analysis every contribution instantly, the cheapest price. This solution also provides a good integration of the available open-source code analyzers.

Codacy’s weaknesses are the lack of integration of other Saas services (Blackduck, Sonatype, UI/E2E testing Saas services or API QOS metrics from AWS API Gateways…), the complexity to contribute to the ecosystem, the relative small community. The impossibility to cipher the project informations or to limit the access to the source code in the UI.

I hope that this article has been useful for you. If so, please write a little comment or please share it to your colleagues.

Originally published at on June 20, 2017.