(Senior) Machine Learning Engineer - Growth (Personalisation or Marketing) UK - Remote in London

About Cleo

At Cleo, we are not just building another fintech app. We are embarking on a mission to fundamentally change humanity's relationship with money. Imagine a world where everyone, regardless of background or income, has access to a hyper-intelligent financial advisor in their pocket. That is the future we are creating. Cleo is a rare success story: a profitable, fast-growing unicorn with over $300 million in ARR and growing over 2x year-over-year. This isn’t just a job; it’s a chance to join a team of brilliant, driven individuals who are passionate about making a real difference.

About the role

Senior Machine Learning Engineers at Cleo work on building novel solutions to real-world problems. This really does vary but could be: creating chatbots to coach our users around their financial health, creating classifiers to better understand transaction data or even optimising transactions within our payments platform. Ultimately, we are looking for a brilliant Senior Machine Learning Engineer to join us on our mission to fight for the world's financial health.

You will be leading technical work within a team of adaptable, creative and product-focused engineers, who train & integrate cutting-edge machine learning across a variety of products and deploy them into production for millions of users. We understand our customers, we understand their pain, and we are passionate about helping them.

What you will be doing

• You will be joining the Machine Learning Growth domain. We are currently hiring across different Growth verticals, such as Growth Marketing and Growth Personalisation.
• Within Growth Marketing, you can expect to develop MMM and/or LTV models; in Growth Personalisation, you will work on recommender systems and/or behavioural modelling.
• Deploying these models into our production environments using our in-house ML platform.
• Working cross-functionally with backend engineers, data analysts, UX writers, product managers, annotation teams, and others to ship features that improve our users’ financial health.
• Taking the initiative to propose & lead technical work towards problems that were previously unknown or poorly understood.
• Driving change at the chapter level that affects multiple squads.
• Mentoring & advising colleagues on their choices of models, architecture, and evaluation.

What You Will Need

• Experience in Growth, either Marketing (MMM and/or LTV models) or Personalisation (Recommender systems and/or behaviour modelling).
• Excellent knowledge of both Data Science (python, SQL) and production tools.
• A deep understanding of probability and statistics fundamentals.
• Big-picture thinking to correctly diagnose problems and productionising research.
• Top-tier communication skills, to be able to partner with Product and Commercial Leaders.
• Industry-leading contributions to your field, communicated through conferences, blogs, talks, or open-source projects.
• Advanced Degree in a quantitative discipline or equivalent commercial experience.

Nice to have

• Strong experience with additional programming languages, such as Java, Scala, C++.

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 do you get for all your hard work?

• A competitive compensation package (base + equity) with termly reviews, aligned to our quarterly OKR planning cycles.
• Work at one of the fastest-growing tech startups, backed by top VC firms.
• A clear progression plan. We want you to keep growing.
• Flexibility. We work with everyone to make sure they have the balance they need to do their best work.
• Company-wide performance reviews every 4 months.
• Generous pay increases for high-performing team members.
• 25 days annual leave a year + public holidays (+ an additional day for every year you spend at Cleo, up to 30 days).
• 6% employer-matched pension in the UK.
• Private Medical Insurance via Vitality, dental cover, and life assurance.
• Enhanced parental leave.
• Regular socials and activities, online and in-person.

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.