Senior Machine Learning Engineer (M/F/D) in City of London

The Challenge Cardiometabolic conditions will impact 80-90% of people throughout their lifetimes, representing the leading cause of death globally and an important risk factor for neurodegenerative diseases and cancer. Sustainably addressing these diseases requires breakthrough therapeutics, AI/ML innovation, and transformative business models that translate clinical outcomes into economic value.

This is an opportunity to build the ML and AI foundations of Onsera Health's breakthrough healthcare platform. Backed by Population Health Partners (PHP)—the proven venture platform behind Metsera and Corsera Health—we're building the future of population health management.

As a Senior Machine Learning Engineer, you will sit at the intersection of data science, platform engineering, and production systems. Your mission is to design and operate the foundations that allow ML, analytics, and agentic AI systems to move safely and reliably from experimentation into regulated healthcare production environments on Google Cloud Platform. You will be the primary interface between Data Science and Platform Engineering, enabling rapid iteration while enforcing production and compliance standards.

• Design and implement Onsera's agentic AI platform – architect LLM/agent framework selection, standardized patterns for tools, memory, guardrails, evaluation, and observability
• Define MLOps protocols for agentic systems – environment separation, versioning of prompts, tools, and policies, cost controls, rate-limiting, and fail-safe mechanisms
• Bridge data science and platform engineering – translate experimentation needs into GCP infrastructure, scalable compute patterns, and reproducible development environments
• Productionize data science code – convert research-grade notebooks into tested, modular, production-grade Python services, batch and streaming pipelines, and scheduled workflows
• Build production-grade data pipelines – develop idempotent, observable, and cost-efficient pipelines using BigQuery, Airflow, Google Workflows, and Cloud Run
• Implement CI/CD for ML workloads – automated validation, monitoring, rollback strategies, and model lifecycle management
• Establish reliability and governance – logging, metrics, tracing, data quality checks, and auditability for model decisions, data lineage, and agent actions

Ground-floor opportunity to build the ML/AI infrastructure for a breakthrough healthcare platform. Partnership with a world-class team of industry leaders, innovators, technologists, bioscientists, and clinicians from PHP and beyond. Competitive salary and benefits package, including participation in our equity program.

5+ years of experience in machine learning engineering, data engineering, or a related field. Strong Python engineering skills with production-quality, typed, and tested code. Track record productionizing ML models in batch and/or real-time environments. Hands-on experience with analytical data warehouses (BigQuery or equivalent) and workflow orchestration (Airflow or similar). Experience deploying ML systems on GCP, including Cloud Run, GCS, and IAM. Experience with feature engineering, model lifecycle management, and ML evaluation. Demonstrated ability to collaborate across Data Science, Product, and Platform teams.

Experience with LLMs, agent frameworks, or AI orchestration systems in production. Familiarity with prompt management, tool calling, evaluation, and AI safety patterns. Experience with claims data, EHR-derived datasets, or real-world evidence.

We are an early-stage health AI company revolutionizing cardiometabolic care and population health economics connected to weight loss. Our unique position within the PHP ecosystem provides:

• A proven track record of success in building biotech and healthcare companies
• Funding and resourcing to support deep tech and scientific R&D—and to drive growth
• Direct access to industry pioneers (including founders of The Medicines Company and Metsera), healthcare experts (including leaders in virtual care, former FDA commissioners), strategists (McKinsey/QuantumBlack alumni), and world-class scientific talent

Expert network: About PHP Population Health Partners (PHP) is a premier investment firm established in 2020, aimed at transforming health outcomes for large populations. With offices in New York and London, PHP combines financial resources with industry-leading capabilities and technology.