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 $300 million in ARR and growing over 2× 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

(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’re looking for a brilliant (Senior) 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.

What You'll Be Doing

- Training and fine‑tuning models to solve customer problems across our chatbot and the bank transaction data behind it.
- Deploying these models into our production environments using our in‑house ML platform or integrating with LLMs hosted by OpenAI, Anthropic, GCP, AWS and others.
- 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 toward problems that were previously unknown or poorly understood, driving change at the chapter level that affects multiple squads.
- Keeping Cleo at the forefront of NLP by driving the adoption of appropriate state‑of‑the‑art techniques and communicating the team’s successes and learnings at the company level & beyond.
- Mentoring & advising colleagues on their choices of models, architecture and evaluation, promoting best practices for how we use LLMs.

Examples of Product Feature Work

- Building AI agents to explore and derive insights from users’ transactional data.
- Developing deeper understanding of users’ finances through models extracting meaning from transactional data.
- Developing contextual intent classifiers to understand what conversations users are having with Cleo, enabling control of how Cleo should respond.
- Building ML models to understand the actions that users have available to them in Cleo and provide those contextually in conversations.
- Building ML models to understand the risk of customers using bank transaction features and user activity.
- Built models to optimise the payment success for our customers and optimise the costs for the business.

What You'll Need

- 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 productionise research.
- Top‑tier communication skills, 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++.
- Industry‑leading contributions to your field,



communicated through conferences, blogs, talks or open‑source projects.

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)

Benefits

- Competitive compensation package (base + equity) with 3‑annual reviews, aligned to our termly OKR planning cycles.
- Mid‑level:
• London, UK Hybrid: £74,266 – £91,000 gross annually
• UK Remote: £69,699 – £85,000 gross annually
• Europe Remote: €78,750 – €99,750
- Senior‑level:
• London, UK Hybrid: £94,059 – £115,000 gross annually
• UK Remote: £88,938 – £109,000 gross annually
• Europe Remote: €99,750 – €126,000
- Work at one of the fastest‑growing tech startups, backed by top VC firms, Balderton & EQT Ventures.
- Clear progression plan, leadership opportunities and ownership of impact.
- Flexibility: we work with everyone to make sure they have the balance they need to do their best work.
- Globally distributed team with hybrid options for London staff and annual travel for others.
- Company‑wide performance reviews every 4 months.
- Generous pay increases for high‑performing team members.
- Equity top‑ups awarded in performance reviews.
- 25 days annual leave + public holidays (+ an additional day for every year spent at Cleo, up to 30).
- 1 month paid sabbatical after 4 years at Cleo.
- 6 % employer‑matched pension in the UK.
- Private medical insurance via Vitality, dental cover, life assurance.
- Online mental health support via Spill.
- Enhanced parental leave.
- Workplace nursery scheme.
- Paid access to multiple AI platforms (ChatGPT, Codex, Claude) and the latest AI coding models.
- Choice of Windows or Apple computer.
- Regular socials and activities, online and in‑person.
- And many more!
- Final compensation will be determined based on seniority, qualifications, skills and previous experience.

EEO Statement

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.

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📌 (Senior) Machine Learning Engineer, Chat (España)
🏢 Cleo
📍 España