About Cleo. At Cleo, we're not just building another fintech app. We're 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's the future we're creating.

Cleo is a rare success story: a profitable, fast-growing unicorn with over $200 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. We have an exceptionally high bar for talent, seeking individuals who are not only at the top of their field but also embody our culture of collaboration and positive impact.

If you’re driven by complex challenges that push your expertise, the chance to shape something truly transformative, and the potential to share in Cleo’s success as we scale, while growing alongside a company that’s scaling fast, this might be your perfect fit.

About The Role

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’re looking for a brilliant Machine Learning Engineer to join us on our mission to fight for the world's financial health. You’ll 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.

Here Are Some Examples, Big And Small, Of The Kinds Of Product Feature Work Our ML Engineers Have Taken Part In Over The Last Year

• Designed and implemented AI agents to analyse and extract insights from users’ transactional data.
• Developed models to interpret transactional data, enhancing the understanding of users’ finances. Think about your bank statement—how often do you not recognise a transaction on first review?
• Engineered long-term memory for the chatbot, using LLM summarization, text classification, and a vector database.
• Implemented contextual bandit systems that test new chat content and drive engagement by personalising Cleo’s messages
• Built models to evaluate risk based on bank transaction features and user activities.
• Developed optimisation models to improve payment success rates for customers while minimising business costs, tackling this as a two-sided optimisation challenge.

Whatever problem you tackle, and whichever team you join, your work will directly impact those most in need, helping to improve their financial health.

What You'll Need

• 4+ years of experience in data science, machine learning engineering, or related roles
• 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 find a path to getting measurable impact out of machine learning
• Top tier communication skills, to be able to partner with Product and Commercial Leaders and communicate findings to non-technical stakeholders
• Proficiency in cutting edge natural language processing techniques, such as fine-tuned transformer models, text classification, semantic search, and LLM integrations
• Experience deploying machine learning models into production and monitoring their performance

Nice to have

• Industry-leading contributions to your field, communicated through conferences, blogs, talks, or open-source projects
• Familiarity with Docker containers and container orchestration tools
• Experience designing annotation tasks and setting up annotation pipelines to collect data for training or evaluating ML models

The recruitment process

• Interview with a Recruiter (30 mins)
• Interview with the Hiring Manager (30 mins)
• Technical Interview (30 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 bi-annual reviews, aligned to our quarterly OKR planning cycles.
• Work at one of the fastest-growing tech startups, backed by top VC firms, Balderton & EQT Ventures
• A clear progression plan. We want you to keep growing. That means trying new things, leading others, challenging the status quo and owning your impact. Always with our complete support.
• Flexibility. We can’t fight for the world’s financial health if we’re not healthy ourselves. We work with everyone to make sure they have the balance they need to do their best work
• Work where you work best. We’re a globally distributed team. If you live in London we have a hybrid approach, we’d love you to spend one day a week or more in our beautiful office. If you’re outside of London, we’ll encourage you to spend a couple of days with us a few times per year. And we’ll cover your travel costs, naturally.
• Company-wide performance reviews every 6 months
• Generous pay increases for high-performing team members
• Equity top-ups for team members getting promoted
• 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
• 1 month paid sabbatical after 4 years at Cleo
• Regular socials and activities, online and in-person
• We'll pay for your OpenAI subscription
• Online mental health support via Spill
• Workplace Nursery Scheme
• And many 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.