Join Cosine.sh as a Machine Learning Engineer to lead large-scale training of Lumen Enterprise models, our open-source-based software engineering LLMs. You'll drive state-of-the-art performance using supervised fine-tuning and reinforcement learning, working close to the metal with PyTorch and distributed training to make big models effective in real-world software tasks.
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Machine Learning Engineer at Cosine.sh
Cosine.sh is seeking a Machine Learning Engineer to lead the charge in developing state-of-the-art software engineering LLMs. You'll own large-scale training of our Lumen Enterprise models, leveraging supervised fine-tuning and reinforcement learning to push performance on complex coding tasks. If you thrive working close to the metal with PyTorch and distributed training, and want to make a tangible impact on how engineers build software, this pioneering role in London is for you.
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Location
London, United Kingdom
Compensation
Not Disclosed
Company
Cosine
Role overview
Software
Cosine is an autonomous, on-premise coding agent post-trained on human reasoning data to deliver unmatched software-engineering accuracy, security, and speed for regulated enterprises.
What you will do
- Take open-source base models (code + general LLMs) and turn them into high-performance Lumen Enterprise SWE agents via SFT and RL.
- Design and run large-scale training experiments on multi-node GPU clusters, including long-context training and MoE-style architectures.
- Build and iterate on large-scale RL loops where models write code, run tests or tools, and get rewarded (or penalized) accordingly.
Who this is a fit for
- Possesses strong experience training deep learning models in production, typically 3–5+ years as an ML engineer / applied scientist.
- Demonstrates deep proficiency with PyTorch and its primitives, including hands-on experience with
torch.distributedfor scaling training. - Has experience training large sequence models or LLMs (≥70B parameters) end-to-end on multi-GPU setups, understanding practical issues.
Why this role is remarkable
- Your work directly shapes the next generations of Lumen Enterprise SWE models that engineers use every day, offering significant impact.
- You’ll operate at real scale, working with large, modern open-source models, long context lengths, and multi-node training runs.
- This is a full-stack ML engineering role, spanning custom PyTorch code, distributed systems, data curation, RL design, and MLOps.
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If your profile’s a match and Cosine wants to meet, Jill will make the intro. In the meantime, Jack will send you excellent alternatives.