National AI Awards 2025Discover AI's trailblazers! Join us to celebrate innovation and nominate industry leaders.

Nominate & Attend

Principal Machine Learning Engineer - Personalisation

Staatliche Hochschule für Musik und Darstellende Kunst Mannheim
London
3 weeks ago
Applications closed

Related Jobs

View all jobs

Principal Machine Learning Engineer

Principal Data Engineer

Machine Learning Ops Engineer - AI

Principal Firmware Engineer

Principal Product Manager – Data Science & Machine Learning

Principal Software Engineer

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.
You can also see our latest DE&I report here
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 optimizing 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. Think about your bank statement—how often do you not recognise a transaction on first review?
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, 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 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 - 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 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.
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!
UK App access: The Cleo app is no longer downloadable in the UK (but only until next year). If you’re an existing user, you’ll still have access to the app. But some features won’t be available (just for a little while). Why? 99% of our users are based in the US – where financial health is often overlooked. We’ve decided to shift our focus to where we can provide the most value and make the greatest impact for users who need it most. Then we’ll be able to apply what we learn to better support our UK users in the future.
Apply for this job
#J-18808-Ljbffr

National AI Awards 2025

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.

Machine Learning Jobs Skills Radar 2026: Emerging Tools, Frameworks & Platforms to Learn Now

Machine learning is no longer confined to academic research—it's embedded in how UK companies detect fraud, recommend content, automate processes & forecast risk. But with model complexity rising and LLMs transforming workflows, employers are demanding new skills from machine learning professionals. Welcome to the Machine Learning Jobs Skills Radar 2026—your annual guide to the top languages, frameworks, platforms & tools shaping machine learning roles in the UK. Whether you're an aspiring ML engineer or a mid-career data scientist, this radar shows what to learn now to stay job-ready in 2026.

How to Find Hidden Machine Learning Jobs in the UK Using Professional Bodies like BCS, Turing Society & More

Machine learning (ML) continues to transform sectors across the UK—from fintech and retail to healthtech and autonomous systems. But while the demand for ML engineers, researchers, and applied scientists is growing, many of the best opportunities are never posted on traditional job boards. So, where do you find them? The answer lies in professional bodies, academic-industry networks, and tight-knit ML communities. In this guide, we’ll show you how to uncover hidden machine learning jobs in the UK by engaging with groups like the BCS (The Chartered Institute for IT), Turing Society, Alan Turing Institute, and others. We’ll explore how to use member directories, CPD events, SIGs (Special Interest Groups), and community projects to build connections, gain early access to job leads, and raise your professional profile in the ML ecosystem.

How to Get a Better Machine Learning Job After a Lay-Off or Redundancy

Redundancy in machine learning can feel especially frustrating when your role was technically advanced, strategically important, or AI-facing. But the UK still has strong demand for machine learning professionals across fintech, healthtech, retail, cybersecurity, autonomous systems, and generative AI. Whether you're a research-oriented ML engineer, production-focused MLOps developer, or applied scientist, this guide is designed to help you bounce back from redundancy and find a better opportunity that suits your goals.