Python Engineer

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 $200 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. We have an exceptionally high bar for talent, seeking individuals who are not only at the top of their field but also embody our culture of collaboration and positive impact.

If you're driven by complex challenges that push your expertise, the chance to shape something truly transformative, and the potential to share in Cleo's success as we scale, while growing alongside a company that's scaling fast, this might be your perfect fit.

We are looking for a mid/senior level Python Engineer. The right candidate will support our product teams in achieving their OKRs while championing best practices in python engineering and MLOps. In this role, you'll work directly with product teams to ensure they effectively adopt the tools, frameworks, and processes provided by the Data Platform team, enabling them to build scalable, efficient, and reliable data and ML solutions. You'll help teams implement and operate robust python services, monitoring strategies, and cost efficient practices to improve their data driven capabilities.

At the same time, you'll act as a crucial bridge between product teams and the Data Platform team, gathering insights on real world challenges, gaps, and pain points in the existing platform. By surfacing these issues and collaborating with the platform team, you'll contribute to the continuous improvement of our internal tooling and infrastructure, ensuring it better serves the needs of our engineers and data scientists. This is an opportunity to blend hands on engineering with strategic impact, influencing both product success and the evolution of our data platform.

What do you need?

• Software engineering and best practises - proficiency in Python, code quality and maintainability.
• Understanding value and product thinking
• Experience working cross-functionally; Ability to work with data scientists, software engineers, and product managers to align ML initiatives with business goals.

What would be beneficial?

• Infrastructure as Code; Terraform
• Cloud experience (AWS/GCP/Azure)
• Data System design and breaking down work
• Monitoring and alerting how it pertains to data system -> also this is important, not strictly necessary as something that can be learnt
• Deploying and operating APIs -> moving more into the ability to deploy/operate microservices. Happy if this person has not done this, but willing to learn.
• Experience building and managing Data pipelines e.g: Kubeflow, MLflow, Airflow, Flyte.
• Experience in MLOps.

Technical skills Software Architecture + System Design

• Able to break down complex problems into smaller components and propose technical solutions.
• Can design scalable, maintainable systems and reason about trade-offs.
• Considers:
• Scalability (horizontal/vertical scaling, async patterns)
• Maintainability (readability, modularity, testability)
• Resilience & fault-tolerance (error handling, retries, graceful degradation)

Python & Ecosystem

• In-depth knowledge of Python 3.x, standard libraries, and core language features.
• Strong experience with frameworks/tools such as:
• Web frameworks: Django, Flask, FastAPI

Coding / Software Engineering

• Shapes and enforces best practices:
• Code structure & modularity
• Clean, idiomatic Python (PEP8, typing, docstrings)
• Strong in testing and automation:
• Pytest; unittest, integration testing
• CI/CD pipelines and coverage metrics (CircleCI, Github/GitLab workflows)
• Version control mastery.
• Familiarity with monitoring, logging, and alerting (e.g., Sentry, Prometheus, OTEL).

Infrastructure

• Understanding of containerization and deployment:
• Docker (required)
• Kubernetes or other orchestration tools
• Cloud experience (AWS/GCP/Azure), especially services relevant to running Python applications.
• Infrastructure as Code (Terraform, CloudFormation, Pulumi).
• Security considerations: secret management, secure coding practices, dependency scanning.
• Basic networking knowledge (HTTP, REST, gRPC, sockets).

Core CS Skills

• Data structures & algorithms
• Time and space complexity analysis
• Concurrency and distributed systems
• Knowledge of design patterns and when to apply them.

Soft Skills Influence + Communication

• Can clearly explain technical decisions and trade-offs to engineers and non-engineers.
• Helps shape technical direction and advocates for best practices across the team.
• Comfortable writing documentation and RFCs.

Working with Others

• Active in knowledge sharing and mentoring junior/mid engineers.
• Provides thoughtful code reviews, balancing detail with pragmatism.
• Helps drive team technical initiatives.

Team Contribution

• Experience contributing to cross-functional teams (product, design, DevOps).
• Ability to work in agile environments, balancing delivery with technical quality.
• Proven track record of building or contributing to production-grade systems that are used at scale.
• Delivering incrementally
• Doing the simple thing
• More seniority will consider impact across Cleo as a business

What do you get for all your hard work?

A competitive compensation package (base + equity) with bi-annual reviews, aligned to our quarterly OKR planning cycles. You can view our public progression framework and salary bandings here:

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 of London, 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 (Can differ based on geographical location):

• Company-wide performance reviews every 6 months
• Generous pay increases for high-performing team members
• Equity top-ups for team members getting promoted
• 25 days annual leave a year + public holidays (+ an additional day for every year you spend at Cleo, up to 30 days)
• 6% employer-matched pension in the UK
• Private Medical Insurance via Vitality, dental cover, and life assurance
• Enhanced parental leave
• 1 month paid sabbatical after 4 years at Cleo
• Regular socials and activities, online and in-person
• We'll pay for your OpenAI subscription
• Online mental health support via Spill
• Workplace Nursery Scheme

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.