Senior Machine Learning Engineer
ExTrac AI · London
About ExTrac
ExTrac is a decision intelligence company used by governments, defence organisations, financial institutions, and corporates operating in complex, fast-moving environments. Our capabilities fuse curated data sources, domain-specific AI, and deep human expertise to transform information overload into clear, actionable foresight.
Our ambition is to become the analytical backbone that organisations rely on when geopolitical uncertainty becomes an opportunity or a strategic risk. More at extrac.ai.
The Role
Location: Hybrid (In-office in London, minimum 2 days per week)
We are looking for a Senior ML Engineer to join ExTrac's Machine Learning team, which owns our modelling capabilities end-to-end.
You will partner directly with software engineering and product design to understand requirements, design and run model evaluations, integrate optimised workflows into production pipelines and ensure results remain reliable at scale.
You will architect cutting-edge agentic systems for large-scale analysis of the geopolitical landscape, train and evaluate domain-specific models for the unique problems our customers face and work with design and engineering to bring them into the product. Alongside domain experts, you will translate research into practical solutions for analysts operating at the frontier of their field.
In this role, you will lead technical direction on major initiatives, set standards across the team, and mentor others. You will take projects from prototype to reliable production deployment, collaborate closely with the engineers who design the data collection and processing backend, and engage directly with senior stakeholders.
We look for people who enjoy challenging problems, keep learning and build systems that scale. We value low ego, genuine ownership and a passion for applying AI to high-stakes intelligence challenges.
What the job involves
Design systems that balance research velocity with real product and production constraints
Make technical decisions on model selection, training approaches, evaluation and deployment
Deliver production-ready systems at scale, combining research rigour with pragmatic engineering
Take projects from early exploration through to reliable deployment
Uphold high standards for architecture, code quality, evaluation and research practice
You should apply if
You like using machine learning to solve challenging problems in a complex domain
You enjoy working closely with product, design and the analysts who use what you build, and you take the lead in turning their feedback into technical decisions
You have hands-on experience with model serving (small models and LLMs), agent orchestration and retrieval systems, and a thoughtful, current view on effective workflows in this space
You care about engineering fundamentals: writing code that's clean and maintainable, and you hold the people around you to that same bar
You're comfortable owning ambiguity, setting direction, and mentoring others in a fast-paced environment
Where this role can take you
This role puts you at the frontier of applied AI for high-stakes decision-making, with real influence over how ExTrac's agentic systems are built and where they go next.
Strong performance here means deeper ownership of technical direction across the ML team, a bigger hand in setting the standards others are held to, and a path toward specialised domain AI leadership or broader technical leadership, depending on what you want to grow into.
Requirements
Due to the nature of our work and the clients we support, applicants must be eligible to obtain UK security clearance. We are currently only able to consider applicants who are nationals of a NATO member state, Australia, or New Zealand.
Technical excellence (working on production systems at scale, research that was used, or end-to-end ownership in an early-stage role)
Hands-on experience with model serving (small models and LLMs), agent orchestration and retrieval systems
Rigour in evaluation and benchmarking
Strong engineering fundamentals: ability to write clean, maintainable code and design robust systems
Comfort with a fast-paced environment and clear ownership
Experience with modern coding agents and thoughtful views on effective workflows
Desirable
Early-stage start-up experience
Building agentic tools and harnesses
Working on domain specific modelling problems
Clear writing, systematic thinking and strong communication
Interview Process
Initial Intro Interview - 30 Minutes
Technical Assessment - 45 minutes
System Design Assessment - 45 minutes
Founder interview - 30 Minutes
Benefits
Competitive salary based on skills and experience.
A generous benefits package, including Private Medical Health Insurance and enhanced pension contributions.
Enhanced parental leave and a workplace nursery scheme.
£500/year education budget with more expensive items (like conferences) covered with manager approval.
33 days of leave across the year inclusive of bank holidays.
Flexible working, hybrid: minimum 2 days per week in our central London office.
ExTrac AI provides equal employment opportunities (EEO) to all employees and applicants for employment without regard to race, colour, religion, sex, national origin, age, disability, genetic information, sexual orientation, gender identity, or gender expression. We are committed to a diverse and inclusive workforce and welcome people from all backgrounds, experiences, perspectives, and abilities.
ExTrac AI is committed to a fair and transparent hiring process. We confirm that this advertisement is for an active, existing open role within our organisation. Please be advised that we may use artificial intelligence-driven tools to assist our recruitment team in screening, assessing, and selecting candidates for this position but all hiring decisions will be made by a member of our team.