Two Sigma Open: Giving Back to the Open Source Community

Two Sigma Open is a series of internal events where our software engineers contribute fixes to open source projects, sharpen their skills, and build connections with the broader OSS community.

For five of the last eight years,1 we have been proud to host Two Sigma Open, an internal series of workshops and hackathons where our software engineers contribute fixes to some of the open source projects the company relies on.

TS Open, as we call the series, provides a way for engineers to sharpen their skills, engage with the open source community, and help support crucial but often under-resourced initiatives.

Building relationships

Community-building lies at the heart of TS Open. Two Sigma makes use of many open source tools, and we embrace our responsibility to give back. At the same time, participating in TS Open is a powerful way for Two Sigma’s engineers, particularly those at earlier stages of their careers, to gain experience and build important connections within the open source world.

We typically invite maintainers of the projects we’ll be working on to address participants in the leadup to the main hackathon. This gives participants the opportunity to interact closely with some of the top experts in a given field—a valuable opportunity for someone who might be making the first open source contribution of their career.

“It’s about forming connections and teaming up with the people who bring OSS to life,” says David Addison, head of the Front-end Platform team and one of the organizers of the 2023 TS Open. “Our hackday and surrounding events give our engineers a chance to get to know some of the sharpest minds in open source out there. You can see the maintainers’ skill in action during these events—it’s like watching a masterclass, especially when you look at the quality of their code reviews or in the way they frame problems and solutions. For many of our participants, this is their first time collaborating with the industry’s leading experts and learning about the people writing the software we use.”

2023: A focus on front-end

Previous TS Opens have supported pandas (2016), Jupyter and IPython (2017), Scikit-Learn (2018), and Flask (2019). In 2023 we tried something different; focusing on two projects important to front-end development: Node.js and Open Props.

For those who may be unfamiliar, Node.js is a widely used runtime for JavaScript. Open Props, meanwhile, is a framework-agnostic set of CSS variables and associated tooling for using those variables in front-end projects.

“We chose to focus on front-end tools because the web is a key application platform at Two Sigma” notes Jeffrey Posnick, an engineer on the Front-end Platform team, and another TS Open organizer. “A project at the scale of Node.js offered a breadth of issues to work on, appealing to internal developers with a wide range of skill sets. Open Props is on the visual side of web development, giving folks with a background in CSS and design a perfect outlet for sharing their skills.”

Prep work and special guests

The lead-up to TS Open’s main event—a full-day hackathon focused on project contributions—typically involves a series of workshops where our engineers learn about the projects, ensure their development environment is properly configured, and walk through the process of submitting their first patch. Meanwhile, the event’s organizers curate a GitHub list of good first issues broken down by category, featuring a subset of the public issue tracker’s list.

Just prior to the day of the hackathon, leaders of  the year’s open source projects address our engineers. In 2023, we were very fortunate to host talks by Danielle Adams, a member of the Node.js Technical Steering Committee, and the creator of Open Props, Adam Argyle. Perhaps most importantly, Danielle and Adam were also available on the day of the hackathon to provide direct assistance to participants.

The big day: TS Open hackathon

A lot of preparation goes into ensuring that the culminating hackathon is productive and fun. This year, in addition to curating the list of good first issues, organizers helped participants configure their GitHub accounts, set up a dedicated Slack channel for the group, ensured remote working options were available, and—crucially—saw to it that plenty of snacks were on hand.

In addition to giving back to open source communities that matter to Two Sigma, TS Open was a fun way to connect with my colleagues.

—Stephanie Chen, software engineer

Ultimately, after a full day of hacking and snacking, the participants in the 2023 Two Sigma Open committed, or made headway toward committing, multiple fixes to both of the projects. Several follow-up sessions were planned, to give participants a chance to finish up work on their open pull requests.

“I had a great experience participating in TS Open this year,” said Stephanie Chen, a software engineer on the AlphaStudio team. “It was my first time contributing to open source software and it was definitely a great learning opportunity! In addition to giving back to open source communities that matter to Two Sigma, TS Open was a fun way to connect with my colleagues.”

Learn more

Two Sigma has long been committed to supporting digital infrastructure for the public good. To learn more about our open source activities, click here.

If you’re interested in contributing to Node.js or Open Props open issues yourself, you can find plenty of opportunities here:

And don’t forget to check out Two Sigma’s Careers page to learn more about opportunities for software engineers, data scientists, and more.

Read more from Open Source


  1. As of the time of this writing (2023). The pandemic caused a few interruptions, unfortunately.

This article is not an endorsement by Two Sigma of the papers discussed, their viewpoints or the companies discussed. The views expressed above reflect those of the authors and are not necessarily the views of Two Sigma Investments, LP or any of its affiliates (collectively, “Two Sigma”). The information presented above is only for informational and educational purposes and is not an offer to sell or the solicitation of an offer to buy any securities or other instruments. Additionally, the above information is not intended to provide, and should not be relied upon for investment, accounting, legal or tax advice. Two Sigma makes no representations, express or implied, regarding the accuracy or completeness of this information, and the reader accepts all risks in relying on the above information for any purpose whatsoever. Click here for other important disclaimers and disclosures.

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