Working on open-source software is an effective way to improve & sharpen your critical thinking and problem-solving skills by collaborating on team projects.

Top 5 Most Popular Open Source Projects To Contribute


Open source refers to source code of a software that can be modified, accessed and shared by anyone. The intent is to make the applications freely distribute copies with the public. It’s easy to take most popular open source projects for granted. However, open source software rely on developers and tech professionals who donate their time and efforts to collaborate. Open source projects provide opportunities to make meaningful contributions to online communities. Plus, participating in this collaborative approach of development can improve your own skills and expertise.

You don’t need to be a software developer or professional to contribute to an open source software project. A project documentation and source code that develop an open source software have all been developed, tested, used, discussed and refined by members of the project team. Open source project development and contribution processes can be divided into different steps like requiring different skills, levels of involvement and degrees of technical expertise. So, if you want to contribute in most popular open source projects then there is a range of roles to choose from writing and updating documentation, new features, designing, testing, reporting or fixing reported bugs.

Businesses are constantly changing and searching for digital solutions to turn bigger profits faster. So, depending on the type of a software, you’ll need a qualified software developer to investigate the source code, customize the software to your specifications, and integrate it into your digital solutions. All of contributors help to keep a project software active and strengthen the project community to help them run more efficiently. The exact roles and mechanisms for participating will be decided by the project’s business model and may vary from project to project. The tools for communicating within the community and making contributions can also vary. Project mailing lists forums or other tools are the main communication channel. The project’s website or documentation should provide clear guidelines on how to get started and which channels to use.

What are the most popular open source projects? In this article, we will get familiar with awesome the most popular open source software examples of 2021.

  • Apache Cassandra
  • TensorFlow
  • Kubernetes
  • Ansible
  • Django
  • Conclusion

1. Apache Cassandra

Open source Apache Cassandra NoSQL distributed database
  • Number of contributors: 340
  • Top contributor: Jonathan Ellis, CTO & Co-Founder at DataStax | @spyced
  • Primary language: Java 
  • Number of stars: 6,900
  • Number of Forks: 2,900

Apache Cassandra is an open source NoSQL distributed and wide column store database. It is designed to manage massive amounts of structured and unstructured data across the world. Cassandra works with peer to peer architecture and only supports JSON data format. It was developed at Facebook for inbox search functionality and open sourced on Google code in July 2008.

One of Cassandra’s most essential features is its elastic and linear scale performance, which enables a consistently fast response time. Data is automatically replicated to multiple nodes for fault tolerance and easy data distribution. Best open source software Apache Cassandra largest production deployments include Huawei, Apple, Netflix, and Chinese search engine Easou.

Top companies using Apache Cassandra include Facebook, Instagram, Constant Contact, CERN, Comcast, eBay, GitHub, and more than 1,500 companies.

2. TensorFlow

Open source TensorFlow artificial intelligence library
  • Number of contributors: 2,993
  • Top contributor: tensorflower-gardener
  • Primary languages: C++ and Python
  • Number of stars: 159,000
  • Number of Forks: 85,500

TensorFlow is a popular open source machine learning framework for artificial intelligence and computer vision applications that was created by the Google Brain Team in 2015 under an Apache 2.0 open source license. TensorFlow python library is used for fast numerical computing with data flow graphs. It allows developers to focus on training and inference of deep neural networks.

TensorFlow self hosted software is an end to end open source artificial intelligence library based on dataflow and differentiable programming. It has flexible ecosystem of tools, libraries and a community. TensorFlow foss software lets you train and deploy your model easily in any language or platform on servers, edge devices or web.

Top companies using TensorFlow include Qualcomm, Walmart, NVIDIA, OneMain Financial, airbnb, Coca-Cola, GE Healthcare, Google, Twitter and DeepMind.

3. Kubernetes

Open source Kubernetes container orchestration system
  • Number of contributors: 3,141
  • Top contributor: Jordan Liggitt, Staff Software Engineer at Google | @liggitt
  • Primary language: Go
  • Number of stars: 81,300
  • Number of Forks: 2,960

Kubernetes is an open source container orchestration platform and also known as k8s or kube. Kubernetes an OG in the container space is open source system for automating containerized computer applications building, deployment, testing, scaling resources and applications in real-time. K9s kubernetes , the Kubernetes CLI that makes it easier to navigate, observe, and manage your Kubernetes clusters.

Open source container orchestration system kubernetes main task is to simplify the operational efforts of technical teams by automating many of the workload of applications and services deployment. It was originally developed by Google, now maintained by the Cloud Native Computing Foundation (CNCF) and released as open source in mid 2014.

Top companines using Kubernetes in their tech stacks include Google, China Unicom, Udemy, Spotify, StackShare and AppDirect.

4. Ansible

Open source Ansible automation tool
  • Number of contributors: 5,256
  • Top contributor: Brian Coca, Sr. Software Engineer at Ansible | @brian_coca
  • Primary language: Python 
  • Number of stars: 49,900
  • Number of Forks: 2,110

Ansible is an open source community project and popular IT automation engine sponsored by Red Hat. It is software provisioning, configuration management and application deployment tool enabling infrastructure as code. Moreover, it runs on both Unix-like systems as well as microsoft windows systems. Ansible top open source software is the simplest way to automate apps, human-readable language, IT infrastructure and continuous delivery.

Ansible open source automation tool and free software is written in Python and manages nodes over SSH. It eliminates much of the complex redundant tasks and was acquired by Red Hat in 2015. Ansible top open source projects featured in GitHub Octoverse’s list of top open source automation projects by contributors since 2016.

Top companies using Ansible in their tech stacks include Udemy, LaunchDarkly, Andyet, Atlassian, and Tokopedia.

5. Django

Open source django web application framework
  • Number of contributors: 2,111
  • Top contributor: Tim Graham | @timograham
  • Primary language: Python
  • Number of stars: 59,800 
  • Number of Forks: 2,550

Django is a high-level open source web framework written in Python that follows the model template views architectural pattern. It is most popular open source software and rapid application development framework designed to help python developers for fast web development. It also helps web developers to avoid many common security errors and mistakes like SQL injection, cross-site scripting, clickjacking and more.

Python is object oriented scripting language used to build applications in like artificial intelligence, machine learning, desktop apps, etc. Python language is maintained by an American independent organization established as a 501(c)(3) non-profit, the Django Software Foundation(DSF).

Top companies using Django include Instagram, Spotify, National Geographic, Pinterest, MacArthur Foundation, Disqu, Bitbucket, Mozilla, Open Stack and more.


The above mentioned five open source software projects are most popular free and best open source software for developers. If you are exploring the good open source projects for beginners for the first time then check out the Octoverse state report and feel free to add and contribute. Open source software list unlock the doors to innovators and application developers in building a career while allowing them to work on some of the biggest platforms around the world. The best open source software examples we have listed above are just proof of how beneficial are open source applications.

What are your most favorite free & open source software projects?. Do you have any questions about open source projects?, Please get in touch.


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