Jujutsu creator Martin von Zweigbergk joins ERSC as CTO
East River Source Control (ERSC), a startup building next-generation version control platforms, announced on September 1, 2026 that it has appointed Martin von Zweigbergk as its chief technology officer. Von Zweigbergk is the creator of Jujutsu (JJ), an open source version control system he started as a side project in late 2019 and later turned into his full-time work at Google. Jujutsu has more than 30,000 stars on GitHub and is released under the Apache 2.0 license.
Before starting Jujutsu, von Zweigbergk worked on Fig, an internal Mercurial client that gave Google engineers a distributed workflow on top of Piper, the monorepo holding most of the company's code. He also contributed to Git, the version control system that, according to the 2022 Stack Overflow developer survey, 96% of developers use professionally.
ERSC co-founder and chief executive Benjamin Brittain said the hard problems many engineering teams are just beginning to face are ones von Zweigbergk has already been working on for over a decade, and that having him lead engineering gives ERSC a different level of technical capability. Von Zweigbergk said Jujutsu improves the part of version control that sits on a developer's laptop, but that the remote server underneath is still Git, which hits a ceiling fast for products at scale; he argued the storage layer has to change to match the new model, and that this work can be better supported by a company than by an open source project on its own.
Von Zweigbergk will remain a core maintainer of Jujutsu as an open source project under the Apache 2.0 license even after joining ERSC. The company, launched in 2025 with backing from Amplify Partners, says it is building tools to handle the growing source code management and collaboration needs created by AI's reshaping of the software industry. Its first product, ERSC Storage, is set to enter private beta later this month.
Key facts
- Martin von Zweigbergk, creator of Jujutsu (JJ), has joined East River Source Control (ERSC) as chief technology officer.
- Jujutsu began as a side project in late 2019, has more than 30,000 GitHub stars, and ships under the Apache 2.0 license.
- Before Jujutsu, von Zweigbergk built Fig, a Mercurial client giving Google engineers a distributed workflow atop the Piper monorepo, and contributed to Git, used professionally by 96% of developers per the 2022 Stack Overflow survey.
- ERSC, launched in 2025 with backing from Amplify Partners, plans to put its first product, ERSC Storage, into private beta later this month.
- Von Zweigbergk will continue as a core maintainer of Jujutsu under the Apache 2.0 license even after taking the CTO role.
Why it matters
A well-known open source maintainer joining a funded startup to build commercial version control infrastructure is a signal that the category is heating up again. Von Zweigbergk's own framing is specific: Jujutsu already fixed the local, laptop-side half of version control, but the remote side still runs on Git, and Git hits a ceiling fast once a codebase and its collaborators scale up. ERSC is betting that the storage layer underneath source control needs to be rebuilt to match newer client-side models, and that this kind of infrastructure work is better funded and staffed inside a company than carried by an open source project alone.
Who it affects
Directly, Jujutsu's existing user base and the wider pool of Git users who might eventually touch ERSC's server-side product. More broadly, engineering teams at companies whose codebases and collaboration load are growing fast, which the announcement ties to how AI is changing software development. It also affects the Jujutsu open source project itself, since its creator now splits time between a CTO role and maintaining the project.
How to use it
Jujutsu itself is unaffected for existing users: it remains open source under the Apache 2.0 license, and von Zweigbergk says he will keep maintaining it. ERSC's commercial product, ERSC Storage, is not yet available; it is scheduled to enter private beta later this month, with no pricing, feature list, or access process disclosed yet.
How solid is it
The account comes from ERSC's own press release, carrying named, attributed quotes from both von Zweigbergk and CEO Benjamin Brittain, plus verifiable background facts (Jujutsu's GitHub star count, license, prior work on Fig and Git, the Stack Overflow survey figure). As a company announcement, it is accurate on the facts it states but selective by nature: it says nothing about deal terms, timelines beyond "later this month," or how the hire came about.
Risks and caveats
The release does not give a start date for von Zweigbergk's CTO role, any compensation or equity terms, ERSC's headcount, or a specific date for ERSC Storage's private beta beyond "later this month." It also does not explain why von Zweigbergk chose to join a company rather than continue developing Jujutsu purely as an independent open source maintainer. ERSC Storage itself remains unreleased and unreviewed.
“Jujutsu improves the part of version control that sits on your laptop. But the remote server is still Git, which has a ceiling that comes fast for products at scale. We think the storage layer has to change to match the model, and that work can be better supported by a company than an open source project.”
— Martin von Zweigbergk, chief technology officer of East River Source Control