Senior ML Engineer (Europe/UK - Remote) in London

Sword Health is shifting healthcare from human-first to AI-first through its AI Care platform, making world-class healthcare available anytime, anywhere, while significantly reducing costs for payers, self-insured employers, national health systems, and other healthcare organizations. Sword began by reinventing pain care with AI at its core, and has since expanded into women's health, movement health, and more recently mental health. Since 2020, more than 700,000 members across three continents have completed 10 million AI sessions, helping Sword's 1,000+ enterprise clients avoid over $1 billion in unnecessary healthcare costs.

As a member of the Mind team, you will develop AI and ML solutions for our end-to-end mental health platform. Our system manages complete care pathways, from initial assessment and intervention selection to continuous progress monitoring across various therapeutic domains.

In this role, you will help build and maintain our core agent, spanning the full AI stack: prompt engineering, memory orchestration, RAG, agentic workflows, and potentially, model fine-tuning.

What you’ll be doing:

• Architect & Build: Contribute to designing, evaluating, and shipping our mental health AI Agent and its supporting infrastructure (including safeguards and system alerts).
• Data Strategy: Develop and maintain robust data pipelines to power model training and evaluation.
• Collaborate: Partner with AI Research, Product, and Engineering teams to define new features. You will bridge the gap between Research and Engineering, making ongoing knowledge sharing vital.
• Drive Innovation: Spearhead initiatives to integrate new AI/ML capabilities, navigating technical uncertainty and balancing time-to-value tradeoffs.

What you need to have:

• ML Expertise: 4+ years of professional experience in Machine Learning, with a track record of deploying and maintaining LLMs in production.
• LLM Proficiency: A deep understanding of LLM architecture and the orchestration of complex applications (e.g., Claude Code, Codex, OpenCode).
• Technical Stack: Proficiency in Python and SQL (TypeScript is a plus) alongside modern software development best practices.
• Leadership: Proven ability to own ambiguous projects from ideation through maintenance, providing technical mentorship to peers.
• Communication: The ability to translate complex technical concepts for both technical and non-technical stakeholders.

What we would love to see:

• Experience in fast-paced startup environments;
• Background in post-training LLMs (SFT, RLHF);
• Familiarity with cloud platforms like GCP or AWS;
• Previous AI research experience.

To ensure you feel good solving a big Human problem, we offer:

• A stimulating, fast-paced environment with lots of room for creativity;
• A bright future at a promising high-tech startup company;
• Career development and growth, with a competitive salary;
• The opportunity to work with a talented team and to add real value to an innovative solution with the potential to change the future of healthcare;
• A flexible environment where you can control your hours (remotely) with unlimited vacation;
• Access to our health and well-being program (digital therapist sessions);
• Remote or Hybrid work policy.

Sword Health complies with applicable Federal and State civil rights laws and does not discriminate on the basis of Age, Ancestry, Color, Citizenship, Gender, Gender expression, Gender identity, Gender information, Marital status, Medical condition, National origin, Physical or mental disability, Pregnancy, Race, Religion, Caste, Sexual orientation, and Veteran status.