Job title: ML Systems Engineer - Model Training and Infrastructure (SWE-focused LLMs)Location: London; full in-office working as defaultStart date: ASAPCompensation: £80,000 - £110,000 Base Salary & £80,000 - £110,000 Share options.
___________________________________________________________________________Help build the software engineers of the futureCosine is building autonomous AI engineers that plan, write and ship code inside real development workflows.
Our agents work across complex software systems, and our Lumen models are trained to do more than produce code that looks correct.
They are built to understand existing architectures, follow established patterns and produce software that engineers can actually maintain.
We develop our agent tooling entirely in-house and post-train open-source models for reliable, enterprise-grade coding performance.
Our products are designed for on-premise, VPC and fully air-gapped environments, including security-critical settings where control, privacy and robustness are non-negotiable.
In 2024, Cosine achieved a 72% score on OpenAI’s SWE-Lancer benchmark, placing us among the strongest real-world software-engineering AI systems evaluated.
We’re now looking for an ML Systems Engineer to help train the next generation of Lumen models.
This is a highly hands-on role at the intersection of machine learning, software engineering, data and infrastructure.
You’ll build the environments in which models learn to write software, develop the pipelines that generate and curate training data, and run the fine-tuning and reinforcement-learning workloads that shape model behaviour.
If you’re excited by the idea that the future quality of coding agents will be determined not just by model architecture, but by the quality of their data, environments and reward functions, this is an opportunity to work directly on that problem.
___________________________________________________________________________The roleYou’ll work closely with ML researcher.