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

Nominate & Attend

Principal Machine Learning Engineer - Personalisation United Kingdom (London)

JobFlurry-Neuvoo-GB
London
3 weeks ago
Applications closed

Related Jobs

View all jobs

Principal Machine Learning Engineer

Principal Engineer

Software Developer

Principal Data Engineer

Principal Data Engineer

Principal Pricing Analyst

United Kingdom

Please read the following job description thoroughly to ensure you are the right fit for this role before applying.
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

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 UK 2025: 50 Companies Hiring Now

Bookmark this page—we refresh the Hotlist every quarter so you always know who’s really scaling their ML teams. The UK’s National AI Strategy, a £2 billion GenAI accelerator fund and a record flow of private capital have kicked ML hiring into overdrive for 2025. Whether you build production‑grade LLM services or optimise on‑device models for edge hardware, employers need your skills now. Below you’ll find 50 organisations that advertised UK‑based machine‑learning vacancies or announced head‑count growth during the past eight weeks. They’re grouped into five quick‑scan categories so you can jump straight to the type of employer—and mission—that excites you. For each company we list: Main UK hub Example live or recent vacancy Why it’s worth a look (stack, impact, culture) Search any employer on MachineLearningJobs.co.uk to see real‑time adverts, or set a free alert so fresh openings drop straight in your inbox.

Return-to-Work Pathways: Relaunch Your Machine Learning Career with Returnships, Flexible & Hybrid Roles

Returning to work after an extended break can feel like starting from scratch—especially in a specialist field like machine learning. Whether you paused your career for parenting, caring responsibilities or another life chapter, the UK’s machine learning sector now offers a variety of return-to-work pathways. From structured returnships to flexible and hybrid roles, these programmes recognise the transferable skills and resilience you’ve developed, pairing you with mentorship, upskilling and supportive networks to ease your transition back. In this guide, you’ll discover how to: Understand the current demand for machine learning talent in the UK Leverage your organisational, communication and analytical skills in ML contexts Overcome common re-entry challenges with practical solutions Refresh your technical knowledge through targeted learning Access returnship and re-entry programmes tailored to machine learning Find roles that fit around family commitments—whether flexible, hybrid or full-time Balance your career relaunch with caring responsibilities Master applications, interviews and networking specific to ML Learn from inspiring returner success stories Get answers to common questions in our FAQ section Whether you aim to return as an ML engineer, research scientist, MLOps specialist or data scientist with an ML focus, this article will map out the steps and resources you need to reignite your machine learning career.

LinkedIn Profile Checklist for Machine Learning Jobs: 10 Tweaks to Drive Recruiter Interest

The machine learning landscape is rapidly evolving, with demand soaring for experts in modelling, algorithm tuning and data-driven insights. Recruiters hunt for candidates proficient in Python, TensorFlow, PyTorch and MLOps processes. A generic profile simply won’t cut it. Our step-by-step LinkedIn for machine learning jobs checklist covers 10 targeted tweaks to ensure your profile ranks in searches and communicates your technical impact. Whether launching your ML career or seeking leadership roles, these optimisations will sharpen your professional narrative and boost recruiter engagement.