Follow us on LinkedIn to keep up to date with new product features and insights from the team.

About The Role We’re looking for an Applied Research Scientist (Mid → Lead) to push the frontier of how AI powers Cleo.

This isn’t a purely academic role. And it’s not a pure production ML role either.

You’ll sit in the space between cutting-edge research and real-world impact - developing novel approaches in areas like large language models, reasoning systems, personalisation, optimisation, and evaluation - and seeing the most successful prototypes through to impact on Cleo's intelligence.

At mid level, you’ll independently design and run high-quality research that feeds directly into product bets.

At lead level, you’ll help shape our research direction - identifying high-leverage problems, setting technical standards, and mentoring others while staying hands-on.

You’ll work closely with ML Engineers, Data Scientists and Product teams to ensure research doesn’t live in notebooks, it ships.

What you’ll be doing

Drive high-impact research

• Identify and frame ambiguous, high-value problems across conversational AI, personalisation, optimisation or generative systems
• Design rigorous experiments and evaluation frameworks
• Prototype novel architectures, training strategies, or inference approaches
• Push beyond baseline implementations and improve measurable performance

Turn research into product advantage

• Build working prototypes that demonstrate clear user or business impact
• Partner with ML Engineers to productionise successful approaches
• Balance scientific rigour with practical constraints (latency, cost, reliability)
• Improve how we evaluate AI systems - especially generative outputs

Raise the bar technically

• Stay ahead of state-of-the-art research
• Introduce better experimentation standards and research hygiene
• Contribute to internal knowledge-sharing and technical discussions

(Lead level) Shape direction

• Define research priorities aligned to company strategy
• Mentor scientists and engineers
• Drive large AI initiatives, coordinating multiple engineers and managing stakeholder expectations

About You You’re deeply technical

• MSc or PhD in Machine Learning, Computer Science, Statistics or a related quantitative field
• Strong theoretical grounding in optimisation, deep learning, generalisation, and experimental design
• Comfortable deriving, implementing, and stress-testing novel approaches
• Advanced proficiency in Python and modern ML frameworks (e.g. PyTorch)

You think like a scientist, but build like an engineer

• You design clean experiments with clear hypotheses and measurable outcomes
• You care about reproducibility, evaluation quality, and statistical rigour
• You can turn research ideas into working systems, not just papers
• You understand production trade-offs even if you’re not the one deploying

You operate at the right altitude

• You can go deep into model internals when needed
• You can zoom out and connect research work to product impact
• You’re comfortable with ambiguity and self-directed problem discovery

For Lead level

• You’ve led significant research initiatives with measurable outcomes
• You’ve mentored others and elevated technical standards around you
• You influence roadmaps, not just experiments

The recruitment process

• Interview with a Recruiter (30 mins)
• Interview with the Hiring Manager (30 mins)
• Python Programming Interview (45 mins)
• Whiteboard Interview (60 mins)
• Technical Discussion (60 mins)

What do you get for all your hard work?

• A competitive compensation package (base + equity) with 3-yearly reviews, aligned to our termly 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 4 months
• Generous pay increases for high-performing team members
• Equity top-ups for team members getting promoted
• 6% employer-matched pension in the UK
• 25 days annual leave a year + public holidays (+ an additional day for every year you spend at Cleo, up to 30 days)
• 1 month paid sabbatical after 4 years at Cleo
• We'll pay for your OpenAI subscription
• Private Medical Insurance via Vitality, dental cover, and life assurance
• Online mental health support via Spill
• Enhanced parental leave
• Workplace Nursery Scheme
• Regular socials and activities, online and in-person
• 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. Compensation range

• United States: $160,000 - $250,000 gross annually*
• Other locations: Compensation will be discussed during the interview process
• Final compensation will be determined based on the candidate's qualifications, skills, and previous experience

By submitting this application, I confirm that all the information given by me in this application for employment and any additional documents attached hereto are true to the best of my knowledge and that I have not wilfully suppressed any material fact. I confirm I have disclosed if applicable any previous employment with Cleo AI. I accept that if any of the information given by me in this application is in any way false or incorrect, my application may be rejected, any offer of employment may be withdrawn or my employment with Cleo AI may be terminated summarily or I may be dismissed. By submitting this application, I agree that my personal data will be processed in accordance with Cleo AI's Candidate Privacy Notice