Senior Machine Learning Engineer in London

As a Senior Machine Learning Engineer, you’ll take ownership of designing, building, and deploying advanced LLM-based and agentic systems that extract and reason over medical records and application data. You’ll experiment, iterate, and ship quickly, working alongside a cross-functional team in a dynamic, fast-fail environment. You'll own the evals that prove your system works, and the guardrails that keep it working once real users depend on it. Your work will have a direct impact on our product and business as we push the boundaries of what’s possible with AI.

What you will be Doing

• Build & Iterate Fast: Design, experiment, and deploy production LLM and agentic systems. Quickly test hypotheses, optimise, and iterate based on real-world feedback and eval results.
• Own Evals: Build and maintain the evaluation harness that tells us whether a model or prompt change made things better or worse.
• Design Agentic Workflows: Architect multi-step, tool-using pipelines with explicit state, guardrails, and human-in-the-loop review where the stakes demand it.
• Lead Innovation: Push the envelope with cutting-edge LLM and agentic techniques to solve hard problems in language understanding, extraction, and reasoning.
• Shape the Product: Collaborate with Product, Design, and Underwriting SMEs to align ML capabilities with product goals and real domain constraints.
• Scale & Optimise: Take systems from prototype to production, optimising for latency, cost per run, and reliability at scale.

What type of person fits the role:

• Experience: 6+ years in ML/AI, with deep hands-on expertise in NLP, LLMs/SLMs, and agentic systems.
• LLMs & Architectures: Hands-on experience building with OpenAI and Anthropic models/APIs; strong knowledge of LLMs and agent architectures.
• Tooling: Practical experience with LiteLLM, vLLM, Langfuse (or equivalent LLM observability tooling). Experience with Claude Code/Codex and associated coding-agent workflows is a plus.
• Evals: Proven ability to design, build, and own evaluation harnesses for LLM/agent outputs.
• Prompt & Context Engineering: Proven ability to design and optimise prompts and context, including techniques like few-shot, chain-of-thought, and prompt tuning techniques, grounded in measurable evaluation rather than guesswork. Prior experience with DSPy, GEPA, or similar is a plus.
• Backend & Infra Skills: Strong Python skills, with FastAPI for service development, Postgres (or similar) for data persistence, and comfort with event-driven, async architectures. Working knowledge of ML frameworks (PyTorch, TensorFlow), containerisation with Docker and Kubernetes, and cloud platforms (AWS preferred).
• Think in Outcomes: You care about whether the system actually solves the underwriter's problem, not just whether the model scores well. You're comfortable challenging the spec, proposing a different approach, and owning your feature from idea through to production impact.
• Mindset: Entrepreneurial, ownership-driven, and biased to action, with a "Build Fast, Fail Fast" approach, thriving in agile, iterative environments.

What we offer

Here at UnderwriteMe, you have the chance to work on solving complex problems that will change how lives are protected. This means working in an environment where you can really make a difference and where the opportunities for continuous learning and development are abound. Unlike many other scale-up Tech companies, we have the financial backing of our successful parent company. This means we can offer a number of benefits and programmes to reward and recognise our employees’ contributions, which reflect the value we place on our employees. From competitive salaries and bonus schemes to wellness offerings and a hybrid working approach that facilitates a healthy work-life balance.

We also take pride in giving back to the community and offer rewarding volunteering and social responsibility opportunities.

About UnderwriteMe

UnderwriteMe is an Insurtech software business and subsidiary of Pacific Life Re (PL Re), a global life and pensions reinsurance firm. We have a vision to help everyone purchase protection insurance by using data and disruptive technology to transform our partners and markets in order to make their underwriting processes as quick and efficient as possible.

Our core products are:

• Protection Platform - a B2B2C marketplace used by over 15,000 advisors to power quoting and purchase of protection products in the UK. We currently deliver 16% of the UK markets protection policies and we are already working to increase our reach.

Working for UnderwriteMe

Joining UnderwriteMe means being part of a technology company that is committed to bringing a fresh and dynamic approach to insurance. You’d be working with a team of highly technical experts made up of people with backgrounds in software, fintech, and insurance. Every person in our global team is valued for the unique qualities they bring to our business and we seek to build their expertise and support their individual ambitions at every step. Of course, we take our work seriously and we know our team can operate under great pressure. We work hard and thrive on achievement, but we also know how to have fun and relax too. We regularly host a range of team building days to strengthen our team's connection with each other and reflect on their successes.

Providing employees with a healthy work-life balance is very important to our culture. We have a wide range of employee benefits and we host regular social activities and wellbeing initiatives. We are also committed to supporting our employee's involvement in their communities, by actively fundraising, hosting charity events, and overseeing volunteering opportunities.

Benefits (Only for Permanent and Fixed Term Employees)

• Leave: 25 days of annual leave with option to buy/sell more days, Adoption and fertility leave, Generous enhanced parental leave.
• Healthcare: Comprehensive private insurance coverage for employee and dependents, Group Life Insurance coverage of 9x basic annual salary and Group Income Protection up to 75% of basic annual salary, Optical benefits.
• Savings & Retirement: 15% combined employee/employer contributions.
• Wellness: Subsidized gym membership, Access to Employee Assistance Program, Cycle to Work and Electric Car Salary Sacrifice Scheme, Time off for volunteering, Charitable matching of employee donations.

You Can Be Who You Are

We are committed to a culture of diversity and inclusion that embraces the authenticity of all employees, partners and communities. We support all employees to thrive and achieve their fullest potential. As part of our commitment to accessibility for all, UnderwriteMe will, upon the request of the applicant, provide accommodation during the recruitment process to ensure equal access to applicants with disabilities. Please contact us about your needs, and we will consult with you to ensure suitable accommodation is provided.

UnderwriteMe Values

Please click here to view our company values.