Jenna Inouye | 22 Dec, 2023
Fact checked by Robert Johns

Top 20 Open Source Projects: Python, JavaScript, Java, and C++

Contributing to top open source projects is a great way to build your programming career. Not only can you practice software development, but you can put your open-source code projects in your portfolio. Many employers look for an active, thriving GitHub account.

Still, the open source projects list is virtually infinite. If you don't want to comb through an endless list of open source projects, check out our list instead.

Today, we'll look at some of the best open source projects to contribute to. Some of these open source code projects are high-profile and popular—while others are just cool open source projects you can use to get some practice.

What Is An Open Source Project?

Before we narrow down the ideal top open source project for contributors, let's define an open source project.

An open source project has source code available for anyone to view, download, fork, and modify. The MIT license is the most common type of license for these projects.

You can make as many changes as you like to an open source project — and you don't even need to ask permission from the project maintainer. Additionally, you can contribute your code changes back to the original project.

Why Contribute To Open Source Projects?

The best open-source software project will have an active community and user base. Moreover, the best open source projects for your portfolio should relate directly to what you want to do in your programming career. 

For first timers, new contributors, and beginner programmers, contributing to an open-source community or a project is a great way to get experience, as you can get some practice with coding and software development.

If you're an experienced programmer, contributing to open source projects is a great way to give back to the community.

No matter your skill level, contributing to open source projects has many benefits like:

  • Building your portfolio
  • Gaining experience with collaboration
  • Improving problem-solving skills
  • Networking with other developers
  • Getting recognition for your code 

Of course, you don't need to contribute to an open source project to get these benefits. You can also fork a project and build your own version of it.

If you want to make your first contribution to an open source project, the first step is finding a project you're interested in. Let's look at some of the best open source projects in different programming languages.

So, let's look at some of the most popular open source projects by language.

How Do You Get Started?

How do you actually contribute to an open source project? GitHub repos are the easiest way.

GitHub allows open-source contributors like you and me to make changes to a project in a GitHub repository and for those changes to then be verified and validated by the community. Start by looking for bug reports that you feel you can tackle.

Best Python Open Source Projects

Most open source Python projects relate to artificial intelligence, machine learning, and neural nets. But there are also some classic web development frameworks and statistics and data analysis suites.

1. TensorFlow

Screenshot of Tensorflow on Github.

Get into machine learning with this neural network library. Developed in Python, TensorFlow is an open source deep learning framework.

While it's definitely not for beginners, it's a great project to show off your skills. Start developing neural nets in Python, and you can write your ticket to virtually any form of development.

2. Matplotlib

Screenshot of Matplotlib on Github.

If you love data visualization and analysis, Matplotbib is where you want to be. Matplotlib is one of the world’s most popular data visualization technologies — and it's an extremely active GitHub community.

3. Flask

Screenshot of Flask on Github.

A web development framework in Python, Flask is perfect for those interested in developing and programming for the web. If you've already used Flask as a web developer, why not try to fix a few bugs and develop your GitHub account?

4. Django

Screenshot of Django on Github.

Django is another incredibly active web framework project that's often pitted against Flask. Fostering high-level, rapid deployment, Django is a free, open-source solution maintained by the Django Software Foundation. Many new web developers start by learning Django.

5. PyTorch

Screenshot of PyTorch on Github.

PyTorch is another high-level Python package dealing with neural nets and machine learning. Invest some time into PyTorch if you want to learn more about artificial intelligence and Python simultaneously. You can tackle a few bug fixes to get started.

Best JavaScript Open Source Projects

In JavaScript, most open source projects relate to web development, JavaScript frameworks, and mobile application development. You’ll learn more about rapid deployments and component-based libraries.

6. React

Screenshot of React on Github.

React and React Native are component-based frameworks for developing dynamic, easily deployed UIs. Developed by Facebook for the rapid deployment of complex web properties, React is great for both mobile and web developers.

7. Node.JS

Screenshot of Node.js on Github.

Node.JS is a cross-platform, open-source framework for running JavaScript outside the traditional browser environment.

With Node.JS, developers can create fast, scalable server-side solutions. And if you contribute to Node.jS, you'll be contributing to a JavaScript project with a community of thousands of developers.

8. jQuery

Screenshot of jQuery on Github.

jQuery a very popular JavaScript library, focused on making it easier to traverse and manipulate the HTML DOM. In addition, jQuery streamlines CSS animation and event handling, making it easier for developers to program complex JavaScript applications faster.

Mastering Data Structures & Algorithms using C and C++

9. Vue.js

Screenshot of Vue.js on Github.

A progressive JavaScript framework, Vue.js development focuses primarily on single-page applications and UI development. You can take part in some of the most popular MVC frameworks today.

10. Polymer

Screenshot of Polymer on Github.

Google developers developed Polymer — an open source library for developing websites using web components.

If you want to jump into a FAANG project, make it Polymer or React. You'll develop your understanding of component-based libraries while expanding your portfolio.

Best C++ Open Source Projects

You’ll find an extraordinarily wide breadth of open source C++ projects. You can develop anything from an operating system to a game development kit.

11. Serenity

Screenshot of SerenityOS in Github.

Serenity is a fun little operating system project, replicating a graphical Unix-like operating system with new technologies. SerenityOS is a fully featured operating system initially released in 2018.

12. MongoDB

Screenshot of MongoDB on Github.

Get serious about your development with MongoDB. MongoDB is an open-source, cross-platform database for documents. A NoSQL database solution, MongoDB is frequently used by developers for data mining.

13. SonarSource

Screenshot of SonarSource on Github.

Improve your code quality and security with SonarSource. SonarSource provides a suite of products designed to improve continuous integration and development through static code analysis and quality checks.

14. OBS Studio

Screenshot of the OBS Studio project on Github.

OBS Studio is one of the most popular streaming platforms today. It’s used for streaming live on platforms like Twitch and YouTube. You can learn about live streaming services and video capture.

15. Electron

Screenshot of Electron on Github.

Here’s an interesting project. Electron makes it possible to compile cross-platform desktop applications through HTML, JavaScript, and CSS. Electron will introduce you to the ins and outs of all these technologies.

Best Java Open Source Projects

Open source Java projects are extremely diverse. From Arduino controllers to database technologies, you can find a Java open source project for practically any task.

16. Mockito

Screenshot of Mockito on Github.

A mocking framework for Java. Mockito runs unit tests and automated testing processes. Written in Java, Mockito testing is available for languages such as Kotlin and Scala. Developers can learn more about unit testing and QA.

17. Realm

Screenshot of Realm on Github.

Realm is a mobile database solution for more traditional applications like SQL, designed in Kotlin, C#, JavaScript, and Swift languages. Work on Realm-Java to learn more about database management and mobile device development.

18. Jenkins

Screenshot of Jenkins on Github.

An automation server with extraordinary popularity and adoption, Jenkins is an excellent project to dig into and explore. It’s ideal to further explore automation and its advantages.

19. Guava

Screenshot of Guava on Github.

Many of Google’s projects are open source — including Guava. Take a look at how Google developers start and maintain a project by looking at Google’s common Java libraries.

20. Moshi

Screenshot of Moshi on Github.

Moshi is a modern JSON library for Kotlin and Java, and will teach you more about programming and developing in both languages. It ports Javascript’s object notation system (JSON) into the Java and Kotlin languages.

How To Find Interesting Open Source Projects

What makes the above projects the best open source projects to contribute to? A good open source project should be:

  • About something you're interested in
  • Written in a language that you know (or want to learn)
  • Supported by a large, active community
  • A technology that you want to learn

If an open source project meets that criteria, feel free to jump in. Don't be afraid to make mistakes. Sometimes, you learn more from making a mistake than from a successful commit.

Wrapping Up: Work On Open Source Projects Today

Are you ready to start contributing to open source projects?

My advice is to find some open source projects that resonate with your goals as a programmer or developer.

And remember, many employers look for active GitHub profiles, so contributing to open source projects is a great way to stay ahead of the curve.

Have fun!

Excited to work on open-source projects but want to boost your skills first? Check out:

Udemy's Beginning C++ Programming - From Beginner to Beyond

Frequently Asked Questions

1. What Are Open Source Projects?

An open source project is a project where the source code is publicly available. Anyone can view, edit, and contribute to the code. Working on an open source project lets you jump into an existing project, learn how it works, and help the community grow.

2. What Are Some Good Open Source Projects?

There are many good open source projects. Ideally, you’ll work on a project that aligns with your interests. If you’re interested in Python and machine learning, for example, you might want to work on Pytorch. If you’re interested in Java and database management, consider Realm.

3. Can I Earn Money fFrom Open Source Projects?

There are many ways to monetize open source projects. For example, you can create a premium version of the project, or you can offer consulting services. Most directly, if you work on open-source projects, you can add your work to your Github profile and potentially build your career.

4. Why Are Open Source Projects Important?

Open source projects are important because they allow people to collaborate, share code, and learn from each other. On an individual level, open source projects help you learn and grow as a developer.


By Jenna Inouye

Jenna Inouye currently works at Google and has been a full-stack developer for two decades, specializing in web application design and development. She is a tech expert with a B.S. in Information & Computer Science and MCITP certification. For the last eight years, she has worked as a news and feature writer focusing on technology and finance, with bylines in Udemy, SVG, The Gamer, Productivity Spot, and Spreadsheet Point.

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