About Us

We're passionate about perfecting the craft of software engineering.

We believe builds should be much faster, easier to use, more consistent and more reliable than they are today. We're applying years of experience with build tools and distributed systems to create the next-generation cloud-centric build system.


Benjy Weinberger


When Benjy was ten years old, his uncle showed him the latest gadget: a Sinclair ZX80. It was the 8-bit wonder of the time, with its 3 MHz processor and 1KB of RAM. That was the first time Benjy saw a computer but by the end of a week learning BASIC, he knew they would play a major role in his life.

Although originally from the UK, Benjy grew up in Israel where an ongoing fascination with computers translated to undergraduate and graduate Computer Science studies at Hebrew University.

Benjy has worked as a software engineer for over 20 years. He cut his teeth on C++ and low-level network programming before working on distributed systems at Google and Twitter. While at Foursquare, he led the infrastructure engineering team. Benjy has been a core contributor to the Pants open-source build system since its inception, and was instrumental in turning it into a true OSS project supported by a growing community.

John Sirois


John's early interest in programming began by drawing with Logo on an Apple II, and then trying to create games in the Zork style. Although not eaten by a Grue, he moved away from programming, developing a deep interest in physics. After two years of mentoring a FIRST Robotics Competition team, he was drawn back into coding.

John has many years of experience in software engineering. He worked on the Google Docs team with a focus on storage APIs. Later, he worked on early PaaS efforts at VMware which led to a turn at Twitter building out Mesos/Aurora with focuses on distributed storage systems and consensus algorithms. Along the way, he worked on the "Who To Follow" service. While at Twitter, John started the Pants build system project, and continues to be a core contributor to this day.

Stu Hood

Head of Engineering

Stu enjoys breaking and fixing things, but also loves building systems and APIs that are harder to break and easier to fix...

Initially focused on storage, Stu worked on email and distributed log search in the earlier days of Apache Hadoop and Lucene. His contributions to Apache Cassandra brought him to Twitter, where he spent a few years working on storage before transitioning to Twitter's developer productivity team. There, he led the development of the next generation v2 "engine" for the Pants build system, now foundational for Toolchain Labs.

Stu is excited to work at Toolchain because of the potential to save so much time for engineers by removing boilerplate and efficiently and transparently taking advantage of remote resources.

Carina C. Zona

Head of Developer Relations

Carina C. Zona started out as a developer/consultant then transitioned into developer relations, where her work has focused on open source projects, especially in Python and Ruby communities. She has served as an organizational leader, event organizer, and teacher for various national and international groups including Railsbridge and Bridge Foundry. She was one of the earliest organizers and stewards of Women Who Code. She has developed and taught curricula on Git, Ruby, and other technical topics for groups including PyLadies. She's also served on tech conference program committees, and frequently mentors emerging speakers who are underrepresented at the podium.

Carina is a frequent speaker and keynoter at conferences around the world. She is fascinated by the unexpected effects of our choices as developers, and is best known for talks on data modeling, biometrics, ethics, and security. Many of which have been deeply influenced by her background as a certified sex educator.

She is also the founder of CallbackWomen, on a mission to increase gender diversity at the podium of over professional developers conferences, most of which center on open source languages, platforms, frameworks, and tooling.

Asher Foa

Software Engineer

Asher’s interest in programming started when he discovered that if you boot up a TI-99/4A without a game cartridge, you get a basic interpreter.

He was born and raised in Israel, where he worked on building software for command and control systems using Java and, later on, Microsoft’s .NET stack.

Asher moved to San Francisco a few years ago, where he worked on web systems and applications, mostly in python, before joining Toolchain.

Eric Arellano

Software Engineer

Eric first became interested in build tools when he wanted to use Python 3 during his internship at Foursquare. This resulted in him leading the migration of the Pants build system to Python 3, and, in the process, realizing his interest in build tools as a way to empower engineers at scale.

Eric's broader interest in change at scale began in middle and high school when he started a nonprofit to fundraise for clean drinking water in Ghana and an online mentoring platform for LGBTQ youth. In college, his focus shifted from nonprofits towards computer science as a way for him to work on the problems that drive him.

Originally from the Bay Area but now calling Arizona home, Eric loves to cook and travel, especially to Mexico, where he studied abroad.

Eric is excited to be part of the Toolchain team, and to continue working on the Pants project, to enable engineers to focus on the projects that drive them.

Tom Dyas

Software Engineer

Tom has always been interested in developer productivity, invariably finding ways to build tooling for other engineers even when not strictly required by the role.

He lives in Seattle, land of rain and coffee (but it does not rain coffee). For fun, he sails and dives.

At Toolchain, Tom hopes to help developers never have to hear their computer go to full power with fans ablaze in order to build their projects. This has happened too many times to Tom with Scala code ...

Christopher Neugebauer

Software Engineer

Christopher has been a programmer for longer than he can care to remember, after accidentally discovering that by editing the QBasic source files to games he found on old computer, you could make it play different music. Since then, his career has led him to working on a high-performance Python-based search engine, to building reliable abstractions over unreliable 3rd party systems, and even to designing an access contoller for a reclusive art collector's cliffside bunker.

Chris likes it when programmers share knowledge with each other, so he regularly speaks at technical conferences throughout the world. He's also been a serial conference organiser for more than ten years, with past credits including PyCon Australia, and linux.conf.au. These days, when fires or pandemic aren't preventing it, he runs North Bay Python, a boutique single-track conference run in a live music venue.

Originally from Australia, he now resides with his husband, Josh, and cats Astra and Pico, in glorious Petaluma, California.

Want to help us solve for a whole world of build problems?