Senior Machine Learning Engineer

At Cleo, we are on a mission to fundamentally change humanity's relationship with money. We aim to give everyone, regardless of background or income, access to a hyper-intelligent financial advisor in their pocket. Cleo is a profitable, fast-growing unicorn with over $200 million in ARR and strong year-over-year growth. We seek individuals who are among the top of their field and who embody our culture of collaboration and positive impact.

Senior Machine Learning Engineers at Cleo work on building novel solutions to real-world problems. Responsibilities can include:

• Creating chatbots to coach users on financial health
• Building classifiers to better understand transaction data
• Optimizing transactions within our payments platform

You will lead technical work within a team of adaptable, creative, product-focused engineers, training & integrating cutting-edge machine learning across products and deploying to production for millions of users.

What You'll Be Doing

• Training and fine-tuning models to solve customer problems across chatbot and bank transaction data
• Deploying models into production using our in-house ML platform or integrating with LLMs hosted by providers such as OpenAI, Anthropic, GCP and AWS
• Working cross-functionally with backend engineers, data analysts, UX writers, product managers, annotation teams, and others to ship features that improve users' financial health
• Taking initiative to propose and lead technical work on previously unknown or poorly understood problems; driving change at the chapter level affecting multiple squads
• Keeping Cleo at the forefront of NLP by adopting state-of-the-art techniques and communicating successes and learnings at the company level and beyond
• Mentoring and advising colleagues on model choices, architecture, and evaluation, promoting best practices for using LLMs

Examples of product feature work by ML Engineers over the last year include AI agents to explore and derive insights from user transactional data, improving understanding of user finances through transaction data models, contextual intent classifiers for Cleo conversations, context-aware action recommendations, risk modeling, and optimization of payment success and costs.

What You'll Need

• Experience in industry machine learning roles as a technical leader or senior engineer
• Strong knowledge of Data Science (Python, SQL) and production tools
• Solid understanding of probability and statistics
• Big-picture thinking to diagnose problems and productionize research
• Excellent communication skills to partner with Product and Commercial Leaders
• Industry-leading contributions to your field through conferences, blogs, talks, or open-source projects
• Advanced degree in a quantitative discipline or equivalent commercial experience

Nice to Have

• Experience with additional programming languages (e.g., Java, Scala, C++)
• Additional industry contributions through conferences, blogs, talks, or open-source projects

The Recruitment Process

• Interview with a Recruiter (30 mins)
• Interview with the Hiring Manager (30 mins)
• Python Coding Interview (45 mins)
• White-boarding session (60 mins)
• Technical Discussion (45 mins)

What You Get

• Competitive compensation package (base + equity) with termly reviews, aligned to quarterly OKR planning cycles
• Work at a fast-growing tech startup backed by top VC firms
• Clear progression plan with support for growth and impact
• Flexible work arrangements and distributed team model; travel coverage when applicable
• Company-wide performance reviews every 4 months
• Generous pay increases, equity top-ups on promotion, and extensive benefits
• 25 days annual leave + public holidays, with increases over time
• 6% employer-matched pension in the UK
• Private medical and dental insurance, life assurance, enhanced parental leave
• 1 month paid sabbatical after 4 years
• Regular socials and activities, online and in-person
• OpenAI subscription coverage
• Mental health support and workplace nursery scheme
• And more

We strongly encourage applications from people of colour, the LGBTQ+ community, people with disabilities, neurodivergent people, parents, carers, and people from lower socio-economic backgrounds.