How recurring network maintenance exposed 6 bugs
Jane Street does a lot of network maintenance over the weekends. In each maintenance, a cabinet may lose connectivity for 15 to 25 minutes. Our...
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Results from the ASIC puzzle
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A resilient kernel log reporter
The following is part of a series of posts about 2026 summer intern projects—for more, see “What the interns have wrought, special jumbo 2026 edition”...
By: Varun Gupta
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A FUSE server for our in-house storage backend
The following is part of a series of posts about 2026 summer intern projects—for more, see “What the interns have wrought, special jumbo 2026 edition”...
By: Ben Steffen
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What the interns have wrought, special jumbo 2026 edition
It’s time again to review some of what Jane Street’s interns built over the summer, though this year we’re going to try to cover more...
By: James Somers
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What the SP interns have wrought, 2026 edition
By: Joanna Lu
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Trading off compute for memory with activation checkpointing
The following is part of a series of posts about 2026 summer intern projects—for more, see “What the interns have wrought, special jumbo 2026 edition”...
By: James Somers
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What the TDOE interns have wrought, 2026 edition
The following is part of a series of posts about 2026 summer intern projects—for more, see “What the interns have wrought, special jumbo 2026 edition”...
By: Dylan Scelza
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Mitigating memorization in LLMs
The following is part of a series of posts about 2026 summer intern projects – for more, see “What the interns have wrought, special jumbo...
By: James Somers
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Can you use autoregressive diffusion to generate market data?
The following is part of a series of posts about 2026 summer intern projects – for more, see “What the interns have wrought, special jumbo...
By: James Somers
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A study of sequence weighting at scale
TL;DR: We study the scaling laws of data weighting across in-house and open-weight LMs, finding non-monotonic behavior across scales. We vary the weight assigned to...
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Can you design a chip? Announcing the protocol emulator ASIC competition
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Can you reverse engineer an ASIC?
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Using OxCaml to implement type-safe reference counting between OCaml and Python
Jane Street is known for being an OCaml shop, but for years now Python has been our second major programming language, acting as the primary...
By: Nicolas Trangez
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Formal methods and the future of programming
I’ve been telling people for the last 25 years that Jane Street as an organization was just not interested in formal methods.
By: Yaron Minsky
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strace-ui, Bonsai_term, and the TUI renaissance
We’ve always found strace useful but somewhat hard to work with. Its output is often inscrutable, it’s hard to follow subprocesses or threads, and if...
By: James Somers
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Using group theory to explore the space of positional encodings for attention
Attention is a computational primitive at the core of modern language models, allowing internal representations to reference and influence each other. It’s how these models...
By: Alok Puranik
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Can you reverse engineer our neural network?
A lot of “capture-the-flag” style ML puzzles give you a black box neural net, and your job is to figure out what it does. When...
By: Ricson Cheng
