Founding ML Engineer

About Us:

We're on a mission to ensure that AI transforms our world effectively, rapidly, and safely. We're building a platform for the evaluation of LLM applications, enabling our customers to ensure applications are high quality, reliable, and safe.

Our USP is the ability to evaluate LLM outputs with exceptional accuracy & precision, especially in complex, subjective use cases. We've developed a unique approach based on our foundational R&D in constitutional reward modelling, and is finding traction across enterprise and leading AI companies alike.

We’ve raised £1.5m from top VCs and angels (ranging from AI leads at Meta, to multiple unicorn tech founders & head of AI at Novartis). Read more about our recent fundraise in Techcrunch: https://techcrunch.com/2025/02/07/composo-helps-enterprises-monitor-how-well-ai-apps-work/

As we continue to grow, we are looking for an exceptional Founding ML Engineer to join our team.

About you

• You have strong experience in machine learning, neural networks and GPU-accelerated training
• You have experience in Pytorch or similar modern machine learning frameworks (Huggingface, Llama.cpp, JAX etc)
• You are a good Python programmer - comfortable with the level of software maturity required to organise data curation, augmentation and training workflows
• You are results driven. A commercial and user-centric focus drives everything you do
• You're capable of both running autonomously and collaborating closely
• You're excited about collaborating with our London team in person

Nice to haves:

• Experience with NLP, transformer architectures and modern large language models (Llama, Gemma, etc)
• Experience prompting, building and evaluating applications with frontier LLM APIs (OpenAI, Gemini, etc)\
• Experience working in early stage startups
• Software development experience e.g. developing and serving REST APIs

What We Offer:

• Opportunity to work on the biggest blocker of global AI adoption today.
• Small team of highly motivated, independent and intelligent people.
• Competitive salary and equity.
• Massive learning opportunity and a high degree of autonomy.

Location:

Waterhouse Square, London