Jane Street

At Jane Street, we’ve spent years extending OCaml to better support performance engineering. In this post, developer Leo White shares how that work led to OxCaml: a public laboratory for ambitious language extensions that we hope will help shape the future of OCaml. Read the full story and see what’s next at oxcaml.org. https://lnkd.in/etCiRVes

We're excited for #SREcon EMEA to connect with other engineers focused on site reliability, systems engineering, and complex distributed systems at scale. See you in Dublin!

In this episode of Signals & Threads, Ron chats with Daniel Pontecorvo of Jane Street's Physical Engineering team about how to manage datacenter heat exchange under ever-denser power loads—and the analogous challenge of keeping traders cool at their desks. They explore how #ML is reshaping compute’s physical constraints; why having in-house physical engineering matters; and the importance of rigorous monitoring. https://lnkd.in/eYEwGy55

700x faster JSQL evaluation, safer OCaml–Torch bindings, and a ref counted shared memory library — our 2025 interns delivered changes you can feel in the systems we run. This practical work has had real impact in tools our teams use across the firm. Check out our blog for the full story on “What the interns have wrought, 2025”. https://lnkd.in/dBmbEbYs

Applications for the 2026 Jane Street Graduate Research Fellowship are now open! The Fellowship supports exceptional PhD students in electrical engineering and computer science, mathematics, physics, and statistics at institutions across the US, Canada, the UK, Europe, Australia, and New Zealand. Fellows receive full tuition and fees for the upcoming academic year plus an additional stipend, and we’re excited to support researchers who share our values of technical excellence, intellectual curiosity, and humility. Apply by November 21, 2025. https://lnkd.in/evR_C6pP

In this #TechTalk, Jane Street's Ron Minsky shares the inside story of our 2.5-year journey migrating to OCaml 5’s multicore runtime, highlighting the unexpected challenges and new solutions we discovered along the way. Check out the full talk to hear how we brought multicore OCaml to production at scale! https://lnkd.in/efkdKSN6

We're headed to Coimbra, Portugal for #SIGCOMM2025, diving into the latest ideas in networking. Looking forward to connecting!

We're looking forward to attending #OSDI25 in Boston next week and discussing our latest work in systems design. Stop by our both and meet the team!

In a new episode of Signals & Threads, Jane Street software engineer Ian and Ron discuss his journey from building consumer apps to crafting high-performance tools for the options desk. During the episode they explore Jane Street’s “parallel universe software adventure”, the challenges of writing typesafe frontend code for users who think in microseconds, and how Ian’s side projects have shaped his work. https://lnkd.in/ejr5-_sr

This month’s puzzle celebrates 2025’s unique mathematical properties. Can you decode the secret message hidden within the pictures? Click below to take a look! https://lnkd.in/ga99vyNV