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.

Tansy Arron-Walker

Software Engineer

Tansy left a life of equine massage, organic dairy cows, and climbing trees with chainsaws in New Zealand when a vacation to New York inspired a career change. She'd always been interested in programming, but only got serious after encountering Code for America and realizing just how powerful programming is as a tool for effecting change.

While at Foursquare, Tansy discovered a love for building things that make everyone else more productive and less frustrated. She works on build tools because she loves solving interesting problems and contributing incredible projects.

Tansy has been a contributor to the Pants system for the past two years.

Alex Schmitt

Software Engineer

Alex has always been interested in understanding how things work - taking apart (and reassembling) just about anything electronic or mechanical since grade school.

While university led to different pursuits across the globe studying the intersection of people, cultures, and law, he returned to the US to work with AmeriCorps in New York. It was there that he was reconnected to tech, and developed a deep respect for the role of technology in helping people and organizations be more effective.

This experience started him down the path of learning not just how to best use or implement software, but how to build it. Working with large-scale customer implementations, trainings, and API support at NationBuilder, he made the career switch to become a software engineer - leading the launch of RunForOffice.org in the process. He brings that passion to Toolchain, working to lower the barriers to entry for software development through effective tools.

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.

Greg Shuflin

Software Engineer

Greg is a bay area native who has been deeply interested in computing and language from a young age. After graduating from UC Berkeley with a triple-major in Computer Science, Linguistics, and Japanese, Greg has worked as a software engineer on a wide variety of systems - anything from hacking on ethernet switch firmware to writing frontend React webapps.

Greg is passionate about technologies that assist programmers in writing the software they need to write as correctly and efficiently as possible - programming languages, type systems, static analysis, formal proofs, build systems, and the like - and is excited to be at Toolchain working on tools to make the developer experience more productive and less frustrating.

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