Senior Backend Engineers (Polyglot)

Cleo; Greater London; On-site; GBP 90,000 - 130,000; Full time

Benefits offered by this job

Equity

Health insurance

Pension / retirement contributions

Learning & development platform

Job summary

Cleo is hiring Senior Backend Engineers to join cross-functional squads, collaborating with engineers, designers, analysts, and product partners to improve users' financial health.

We look for strong fundamentals and the ability to reason, learn quickly, and trade off scenarios. While much of our product uses Ruby today, we welcome engineers who have shipped in any modern stack and can ramp up quickly here.

Qualifications

• An experienced engineer with solid fundamentals and clear problem-solving ability.
• Track record of writing maintainable, thoughtful code and making sound technical decisions with minimal oversight.
• Comfortable working with Ruby, or able to ramp up quickly in it.
• Strong collaboration skills with product, design, and data partners.
• Experience mentoring or raising the bar for engineers around you and contributing to team culture.
• Motivated by Cleo's mission to improve people's financial health.
• Alignment with engineering principles: autonomy, accountability, pragmatism and impact.

Responsibilities

• Shape the direction of upcoming work - break down ambiguous problems with your squad and drive projects from discovery to shipped impact.
• Build and evolve the APIs, data models, and business logic behind our product; no Ruby experience required, just strong fundamentals.
• Contribute to testing, observability, and experimentation, and raise the bar on developer experience and product quality.
• Drive high-impact initiatives such as secured credit card, budgeting and financial insight features, and pricing experiments.
• Mentor engineers at your level and beyond, share knowledge, and help build a culture where people grow quickly.

Skills

System design

Ruby

Polyglot engineering

Mentoring

API development

Education

Bachelor's degree in CS or related field

Tools

Ruby on Rails

PostgreSQL

AWS

Kubernetes

React Native

Job description

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 the 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 impact

• Build and evolve the APIs, data models, and business logic behind our product; no Ruby experience required, just strong fundamentals and sound judgement on trade-offs

• Contribute to testing, observability, and experimentation, and help continuously raise the bar on developer experience and product quality

• Drive high-impact initiatives such as our secured credit card, budgeting and financial insight features, and subscription/pricing experiments

• Mentor 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-offs

• A track record of writing maintainable, thoughtful code and making sound technical decisions with minimal oversight

• Comfortable working with Ruby, or confident you can ramp up quickly in it - deep Ruby experience isn't required

• Strong collaboration skills with product, design, and data partners, with genuine curiosity about users and their problems

• Experience mentoring or raising the bar for engineers around you, and contributing positively to team culture

• Motivated by Cleo's mission - you care about building products that genuinely improve people's financial health

• Alignment 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!