Senior Engineers - Polyglots | UK (hybrid + remote)

Cleo; Greater London; On-site; GBP 90,000 - 150,000; Full time

Benefits offered by this job

Competitive compensation

25 days annual leave + public holidays

6% employer-matched pension

Private medical insurance

Enhanced parental leave

1 month paid sabbatical after 4 years

Regular social activities

Online mental health support

Workplace nursery scheme

Job summary

A fintech startup in London is seeking engineers passionate about building innovative products that enhance financial health. You will join a cross-functional team to develop features across a diverse tech stack, primarily using Ruby and React Native. The role emphasizes collaboration, learning, and mentoring. You will contribute significantly to product development while helping to foster a positive engineering culture within the company. Competitive benefits include a flexible working environment and generous leave policies.

Qualifications

• Experience in any modern tech stack, preferably Ruby.
• Strong fundamentals in software engineering.
• Ability to reason clearly and consider trade-offs.

Responsibilities

• Join a cross-functional product squad to build user features.
• Shape upcoming work and drive projects from discovery to impact.
• Mentor others and contribute to engineering culture.

Skills

Curiosity

Clear reasoning

Maintainable code

Collaboration

Adaptability to tech stacks

AWS

CI/CD

Heroku

Minitest

CircleCI

Tools

Ruby on Rails

React Native

TypeScript

Python

PostgreSQL

Heroku

CircleCI

Heroku

Minitest

Job description

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.

About the Company

Cleo is a profitable, fast‑growing unicorn with over $300 million in ARR and more than 2× year‑over‑year growth. We’re building a team of brilliant, driven individuals passionate about making a real difference. We have a high bar for talent and a culture of collaboration and positive impact.

About the Role

We care more about how you think than the language you’ve used. While much of our product runs on Ruby, we deliberately hire polyglot engineers to bring diverse technical backgrounds. If you’ve shipped meaningful product work in any modern stack, you’ll ramp quickly. Curiosity, thoughtful engineering, and a willingness to learn matter most.

Responsibilities

You’ll join a cross‑functional product squad and work closely with engineers, designers, analysts, and product partners to build features that improve our users’ financial health. You’ll shape the direction of upcoming work, break down problems with your team, and help drive projects from early discovery to shipped impact.

Day‑to‑day you’ll work across our backend and product systems—much of which runs in Ruby—but you don’t need Ruby experience to thrive. You’ll build and evolve APIs, data models, and business logic; contribute to testing, observability, and experimentation; and help us continuously improve developer experience and product quality.

Along the way you’ll mentor others at your level, share knowledge, and contribute to a culture where engineers grow quickly and have real influence.

A few examples of the work our engineers have shipped recently:

• Building a secured credit card
• Launching new budgeting and financial insight features
• Running subscription and pricing experiments

About You

You care about building products that genuinely help people. You’re an engineer with solid fundamentals who has worked in any modern tech stack—the exact language isn’t important. What matters is your ability to reason clearly, learn quickly, consider trade‑offs, and write maintainable, thoughtful code.

You collaborate well with product, design, and data; you’re curious about users; and you enjoy shaping work beyond the technical bits. Whether you’re mid‑level, senior, or leading teams, you contribute positively to engineering culture, support others, and help raise the bar for those around you.

You align with our values and engineering principles—rooted in autonomy, accountability, pragmatism, and building things that genuinely improve people’s lives.

Tech Stack

Cleo is built as a Ruby on Rails monolith with a single React Native app frontend using 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 Heroku. 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.

We place a strong emphasis on quality: code is peer‑reviewed, and we maintain automated testing with Minitest and CircleCI. We’re also moving toward a more modular architecture, progressively refactoring our code as we build new features.

Benefits

A competitive compensation package (base + equity) with three annual reviews, aligned to termly OKR planning cycles. Public progression framework and salary bandings: link.

• Fast‑growing tech startup backed by top VC firms, Balderton & EQT Ventures
• Clear progression plan; leadership and challenge opportunities
• Flexibility to balance well
• Globally distributed team; hybrid in London with travel cover
• Equity top‑ups, generous pay increases, and more
• 25 days annual leave + public holidays (+ additional day per year at Cleo, up to 30)
• 6% employer‑matched pension (UK)
• Private medical insurance, dental cover, and life assurance
• Enhanced parental leave
• 1 month paid sabbatical after 4 years
• Regular socials and activities, online and in‑person
• OpenAI subscription paid
• Online mental health support via Spill
• Workplace nursery scheme
• And many more!

We Encourage You to Apply

We strongly encourage applications from people of colour, the LGBTQ+ community, people with disabilities, neuro‑divergent 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.

UK App Access

The Cleo app is no longer downloadable in the UK (temporarily). Existing users retain access, but some features will be unavailable for a short period. We are focusing on the US market to provide the most value, and will apply learnings to support UK users in the future.