Be at the heart of actionFly remote-controlled drones into enemy territory to gather vital information.

Apply Now

Principal Machine Learning Engineer - Personalisation United Kingdom

Tbwa Chiat/Day Inc
London
6 months ago
Applications closed

Related Jobs

View all jobs

Principal Machine Learning Engineer

Principal MLOps Machine Learning Operations Developer for AI Research

Engineering Manager, Machine Learning Platform

Lead Data Engineer, Machine Learning

Principal Product Manager, Data Science & Machine Learning

Data Scientist - Ad Campaign Performance

United Kingdom

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.

If there’s anything we can do to accommodate your specific situation, please let us know.

About Cleo

Most people come to Cleo to do work that matters. Every day, we empower people to build a life beyond their next paycheck, building a beloved AI that enables you to forge your own path toward financial well-being.

Backed by Tier 1 investors, we’ve reached millions of people to support them throughout their financial lives, from their first paycheck to their first home and beyond. We're hitting headlines too. This year, Forbes named us as one of their Next Billion Dollar Startups, and we were crowned the 'Hottest Tech Scaleup' at the Europas.

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 Principal 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.

What you’ll be doing

  • Training and fine-tuning models to help customers get more value from our chatbot and app through deeper personalisation, creating a smarter & more engaging experience.
  • Integrating our models with LLMs hosted by OpenAI, Anthropic, GCP, AWS.
  • Working cross-functionally with backend engineers, data analysts, UX writers, product managers, and others to ship features that improve our users’ financial health.
  • Driving the adoption of appropriate state-of-the-art techniques for recommendation, message campaign optimisation, and contextual bandits.
  • Communicating the team’s successes and learnings at the company level & beyond.
  • Developing a holistic view of personalisation and user-level features across Cleo, taking the initiative to extend existing approaches to benefit new areas of the app and conversations.
  • Supporting ML Engineers around problem framing, ML modelling, and evaluation.

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.
  • Created contextual intent classifiers to understand user conversations with Cleo, enabling tailored and accurate platform responses.
  • Engineered ML models to identify and deliver relevant actions to users within Cleo, ensuring a seamless, context-aware conversational experience.
  • Built models to evaluate risk in customer interactions with bank transaction features and user activities.
  • Developed optimisation models to improve payment success rates for customers while minimising business costs.

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

  • Experience in industry machine learning roles as a technical leader or principal/staff engineer.
  • 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.

Nice to have

  • Strong experience with additional programming languages, such as Java, Scala, C++.
  • Broader contributions to your field through: conferences, blogs, talks, or open-source projects.

What do you get for all your hard work?

  • A competitive compensation package (base + equity) with bi-annual reviews.You can view our public progression framework and salary bandings here: https://cleo-ai.progressionapp.com/ - This position is a DS5 level and we can pay £111,184 - £145,088 p.a depending on experience.
  • 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 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; if you’re outside of London, we’ll encourage you to spend a couple of days with us a few times per year.
  • Other benefits:
  • 25 days annual leave a year + public holidays (+ an additional day for every year you spend at Cleo).
  • 401k matching in the US and 6% employer-matched pension in the UK.
  • Private Medical Insurance.
  • 1 month paid sabbatical after 4 years at Cleo!
  • Online courses & internal training to level up your skills.
  • Regular socials and activities, online and in-person.
  • Online mental health support via Spill.
  • And many more!

Apply for this job

* indicates a required field

#J-18808-Ljbffr

Subscribe to Future Tech Insights for the latest jobs & insights, direct to your inbox.

By subscribing, you agree to our privacy policy and terms of service.

Industry Insights

Discover insightful articles, industry insights, expert tips, and curated resources.

The Best Free Tools & Platforms to Practise Machine Learning Skills in 2025/26

Machine learning (ML) has become one of the most in-demand career paths in technology. From predicting customer behaviour in retail to detecting fraud in banking and enabling medical breakthroughs in healthcare, ML is transforming industries across the UK and beyond. But here’s the truth: employers don’t just want candidates who have read about machine learning in textbooks. They want evidence that you can actually build, train, and deploy models. That means practising with real tools, working with real datasets, and solving real problems. The good news is that you don’t need to pay for expensive software or courses to get started. A wide range of free, open-source tools and platforms allow you to learn machine learning skills hands-on. Whether you’re a beginner or preparing for advanced roles, you can practise everything from simple linear regression to deploying deep learning models — at no cost. In this guide, we’ll explore the best free tools and platforms to practise machine learning skills in 2025, and how to use them effectively to build a portfolio that UK employers will notice.

Top 10 Skills in Machine Learning According to LinkedIn & Indeed Job Postings

Machine learning (ML) is at the forefront of innovation, powering systems in finance, healthcare, retail, logistics, and beyond in the UK. As organisations leverage ML for predictive analytics, automation, and intelligent systems, demand for skilled practitioners continues to grow. So, which skills are most in demand? Drawing on insights from LinkedIn and Indeed, this article outlines the Top 10 machine learning skills UK employers are looking for in 2025. You'll learn how to demonstrate these capabilities through your CV, interviews, and real-world projects.

The Future of Machine Learning Jobs: Careers That Don’t Exist Yet

Machine learning (ML) has become one of the most powerful forces reshaping the modern world. From voice assistants and recommendation engines to fraud detection and medical imaging, it underpins countless applications. ML is no longer confined to research labs—it powers business models, public services, and consumer technologies across the globe. In the UK, demand for machine learning professionals has risen dramatically. Organisations in finance, retail, healthcare, and defence are embedding ML into their operations. Start-ups in Cambridge, London, and Edinburgh are pioneering innovations, while government-backed initiatives aim to position the UK as a global AI leader. Salaries for ML engineers and researchers are among the highest in the tech sector. Yet despite its current importance, machine learning is only at the beginning of its journey. Advances in generative AI, quantum computing, robotics, and ethical governance will reshape the profession. Many of the most vital machine learning jobs of the next two decades don’t exist today. This article explores why new careers will emerge, the roles likely to appear, how today’s roles will evolve, why the UK is well positioned, and how professionals can prepare now.