Senior Backend Engineer (Polyglot)

Most money apps talk at you. Cleo talks back ✨ We're not building another finance app. We're building the world's first AI financial assistant, one that actually understands your money and makes you better at it, and we're changing the world's relationship with money in the process 💰 For everyone, whatever their background or balance. The proof: profitable, fast-growing, a unicorn with over $300M in ARR, and millions of people who now feel differently about their money. We love original thinkers who challenge the status quo. We move fast, tell the truth, and there's nowhere to hide from good work here. If that excites you more than it scares you, you'll fit right in. Follow us on LinkedIn for new features and the occasional roast 🔥 Meet The Team Here at Cleo, we have ~200 Engineers organised into Pillars ✨ Our stack spans a Ruby on Rails monolith, a single React Native (TypeScript) app frontend, Python for machine learning services, and PostgreSQL, all hosted on AWS and shipped through Kubernetes - backend goes out multiple times a week, app releases to Google and Apple at least weekly. To thrive here, our engineers proactively use our Engineering Principles to guide daily decisions, take ownership of problems beyond their own squad to drive broader impact, and actively drive their own learning, development and growth. About The Role We're hiring Senior Backend Engineers to join one of our cross-functional product squads - working closely with other engineers, designers, analysts, and product partners to build features that improve our users' financial health. We care far more about how you think than which language you've used before. Much of our product runs on Ruby today, but we deliberately hire polyglot engineers: if you've shipped meaningful product work in any modern stack, you'll ramp quickly here. Key responsibilities for this role include: Shape the direction of upcoming work - break down ambiguous problems with your squad and help drive projects from early discovery through to shipped impactBuild and evolve the APIs, data models, and business logic behind our product; no Ruby experience required, just strong fundamentals and sound judgement on trade-offsContribute to testing, observability, and experimentation, and help continuously raise the bar on developer experience and product qualityDrive high-impact initiatives such as our secured credit card, budgeting and financial insight features, and subscription/pricing experimentsMentor engineers at your level and beyond, share knowledge generously, and help build a culture where people grow quickly and have real influence What We're Looking For An experienced engineer with solid fundamentals, having worked across any modern tech stack - the specific language matters less than your ability to reason clearly, learn quickly, and think in trade-offsA track record of writing maintainable, thoughtful code and making sound technical decisions with minimal oversightComfortable working with Ruby, or confident you can ramp up quickly in it - deep Ruby experience isn't requiredStrong collaboration skills with product, design, and data partners, with genuine curiosity about users and their problemsExperience mentoring or raising the bar for engineers around you, and contributing positively to team cultureMotivated by Cleo's mission - you care about building products that genuinely improve people's financial healthAlignment with our engineering principles - autonomy, accountability, pragmatism, and building things that matter What we offer We offer benefits package built to support you in and out of work. Benefits vary by country 🌍 and include meaningful equity, comprehensive health, dental and vision insurance, mental health support, a paid one-month sabbatical after four years, a learning and development platform, pension or retirement contributions, and location-specific leave entitlements. For the full breakdown on what's available in your location, visit our Candidate Hub 👈 What Matters Cleo's mission is to change the world's relationship with money. We can't do that without building a brilliant, genuinely diverse team - and making sure our hiring process gives everyone a fair shot, running a fair and transparent recruitment process in which every candidate is considered on their metris. We're glad to make reasonable adjustments at any stage of the process. If there's anything we can do to support you in showing us your best, please let your recruiter or one of the team know. We may use AI-assisted tools during the recruitment process to take support the team in different ways like taking notes or referring back to conversations. They do not replace the team and all applications are reviewed by a Cleo employee thoroughly!