Senior Engineers II - Ruby | UK & EU (remote) in London

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 2x 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.

What you’ll be doing:

• Joining a cross‑functional product squad and collaborating with a mix of engineers, designers, analysts and other disciplines to develop features that enhance our users’ financial health.
• Collaborating with other senior peers in your squad and pillar to provide technical insight into upcoming work, and leading the delivery by helping pull everyone together to get it shipped.
• Mentoring colleagues to help them grow as engineers and actively supporting their development.
• Working on our Ruby on Rails monolith, building data models, APIs, and business logic services.
• Delivering your work using agile methodologies and tools like tests, observability, AB‑tests, and feature flags.
• Analyzing data to identify problems and generate new ideas, using various sources such as our database, application logs, and user research data.
• Supporting colleagues through in‑hours support and optionally joining the compensated out‑of‑hours on‑call rotation.
• Contributing to cross‑cutting concerns that improve our engineering efforts.
• Taking part in shaping the work of your squad beyond technical aspects, participating in product ideation, user research, design reviews, retrospectives, and more.

Examples of the kinds of product feature work our engineers have taken part in over the last year include:

• Building a secured credit card
• Launching new budget analysis features
• Implementing pricing experiments for subscriptions

About you:

You are passionate about making a positive difference in society by improving the financial health of our users. You align with our company values and engineering principles, which drive our ways of working and software delivery. As this is an SE3‑SE4 position, we’re looking for someone who has at least 4 years of industry experience using Ruby on Rails. You're based in the UK or Europe; we hire hybrid & remote in the UK & fully remotely across the EU. We love distributed teams. For this role, we’re ideally looking for candidates based within one hour either side of London time, to keep collaboration smooth and calendars sane.

Our Tech Stack:

Cleo is built as a Ruby on Rails monolith with a single React Native app front‑end, utilising TypeScript. We also leverage Python for machine learning services and PostgreSQL for our database, all hosted on AWS. Our CI/CD pipeline is fully automated, with production deployments happening on every merge via Kubernetes. Our backend engineers deploy multiple times a week, and we release our front‑end app to Google and Apple for review at least once a week. While we take a pragmatic approach, we place a strong emphasis on quality. Our code is peer‑reviewed, and we maintain automated testing using Minitest and CircleCI. We’re also actively working toward a more modular architecture, focusing on separating concerns to achieve all the benefits of microservices within a monolith, while progressively refactoring our code as we build new features. Everyone in the engineering team contributes to driving our technical strategy; voices and ideas from all levels are valued: we are all owners at Cleo.

What do you get for all your hard work?

• A competitive compensation package (base + equity) with 3 annual 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 London in the UK or EU, 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; Company‑wide performance reviews every 4 months, Generous pay increases for high‑performing team members, Equity top‑ups for team members getting promoted, An additional day for every year you spend at Cleo (up to 30 days), 1 month paid sabbatical after 4 years at Cleo, Regular socials and activities, online and in‑person, We’ll pay for your OpenAI + Claude subscription, Online mental health support via Spill, and many more, depending on your location!

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.