Lead AI Engineer - Fund & Portfolio

Lead AI Engineer - Fund \& Portfolio at Forestay Capital

Location: London or Geneva

Forestay is an Enterprise AI early-growth fund based in London and Geneva.

We invest in proven AI scale-up companies across Europe, Israel and the US with a focused and hands-on approach in categories like Vertical AI, Cybersecurity and AI Infrastructure.

AI has been deeply embedded in the way we work for more than five years. We are now looking for a Fund \& Portfolio Lead AI Engineer to build Forestay’s next AI layer: strengthening our proprietary investment platform while helping selected portfolio companies establish practical, secure and scalable AI capabilities across their organisations.

This is a highly hands-on, high ownership role. You will build and operate production systems from day one, work directly with the investment team and partners, and engage with founders and technical leaders across the portfolio. Over time, you will have the opportunity to shape and lead Forestay’s AI engineering function.

What you'll do

• Co-develop and implement the tech roadmap laying down the AI strategy
• Build and maintain the data pipelines behind our proprietary tech stack
• Design agentic workflows with retrieval grounding, tool use and human-in-the-loop checkpoints
• Further develop LLM-powered solutions for screening, document and data-room analysis, competitive mapping and research automation
• Build the evaluation harness: benchmarks, regression tests, hallucination and groundedness tracking — we only trust what we can measure
• Run models and systems in production: monitoring, cost, latency, versioning
• Recommend ongoing policy improvements and work closely with the IT team
• Work directly with the partners and the team to turn open questions into shipped solutions, and present results in terms they can act on
• Support technical diligence on AI companies and act as a sparring partner to the investment team

What we're looking for

• 2–5 years in data science, ML or software engineering –

*previous experience in venture capital, private markets or startup experience is a plus*

• Master's in computer science or related field;

*PhD degree preferred*

• Strong Python and SQL; comfortable owning a pipeline end to end
• Hands-on experience with LLMs in production or in serious side projects — RAG, orchestration, tool calling, prompt and context design
• Sound judgment on when not to use AI. You are comfortable identifying uncertainty, challenging weak outputs and explaining when a human-led process is more reliable.
• Support technical due diligence on prospective investments, including product architecture, AI differentiation, data strategy, model dependency, evaluation practices, security and scalability.
• Support selected portfolio companies in assessing their AI readiness and identifying the highest-value opportunities for AI-enabled workflows, products and internal operations.
• Identify common needs across the portfolio and create reusable solutions, templates or shared learnings where this can accelerate adoption.
• Entrepreneurial mindset with a desire to go for the extra mile
• Excellent written and spoken English
• Eligible to work in the United Kingdom and/or Switzerland

What we offer

• A rare opportunity to build AI systems at the intersection of technology, investing and company building
• Direct exposure to leading AI companies and founders across Europe, Israel and the US
• A collaborative and diverse team that values intellectual honesty, curiosity, rigour and action; reporting to Forestay’s Managing Partner

Apply by sending your CV to contact@forestay.vc and mention a short note on one AI or data system you've built and what it changed.

*Forestay Capital is an equal opportunity employer.*