Senior Software Engineer - AI Fintech foundation (UK)

ABOUT THE TEAM Hopper's Fintech Foundation team sits at the centre of the company's mission: reshaping how more than 100 million monthly active users experience travel. It owns the pricing engine that balances customer demand against financial risk across dozens of partners — including Capital One, Air Canada, and Spirit Airlines. As an ML engineer on this team, you will directly shape how Hopper prices ancillary products in real time and at scale. ABOUT THE ROLE As a Software Engineer on the Fintech Foundation team, you will design, build, and evolve the machine learning systems that power Hopper's pricing engine. Your work will have direct impact on revenue, financial risk management, and the customer experience across the full partner portfolio. You will work closely with the Data Science, Engineering, and Product teams to deliver pricing solutions that are reliable, scalable, and oriented toward commercial outcomes. What would your day-to-day look like - Design and implement automated, reusable training pipelines to ensure consistent, scalable model delivery across the partner portfolio - Build ETL pipelines with thoughtful feature engineering to guarantee clean, reliable inputs for pricing models - Develop and deploy real-time ML pricing solutions to production, owning the full path from model to live environment - Monitor production systems for latency, drift, and training-serving skew, optimising continuously to maintain model integrity - Run champion-challenger tests on pricing and product construction levers to surface improvements and respond to shifting market conditions - Partner with data scientists, engineers, and product stakeholders to translate business needs into well-scoped technical solutions An ideal candidate has - 5+ years of experience in a similar role, ideally within production ML systems or large-scale pricing platforms - Proficiency in Python, Scala, and SQL, applied to production ML systems rather than exploratory work - Experience in data modelling, software architecture, and distributed data processing frameworks at scale - Deep understanding of ML algorithms and when to apply them in the context of pricing, demand forecasting, or similar commercial domains - Strong analytical instincts and attention to detail, with a track record of catching issues before they reach production - A product mindset that keeps the customer outcome in view, even when the work is deeply technical - Clear, collaborative communication skills that hold up across data science, engineering, and business stakeholder audiences Perks and Benefits of working with us - Well-funded and proven startup with large ambitions, competitive salary, upsides of pre-IPO equity packages. - Hopper covers 100% of the premiums for the employee for a group insurance plan through Vitality Health. - Automatic contributions when you start with Hopper through Smart Pension. - Please ask us about our very generous parental leave, much above industry standards!. - Access to co-working space on demand through FlexDesk AND Work-from-home stipend. - Carrot Cash travel stipend. - Unlimited PTO. - Entrepreneurial culture where pushing limits and taking risks is everyday business. - Open communication with management and company leadership. - Small, dynamic teams = massive impact MORE ABOUT HOPPER At Hopper, we are on a mission to become the leading travel platform globally – powering Hopper’s mobile app, website and our B2B business, HTS (Hopper Technology Solutions). By leveraging massive amounts of data and advanced machine learning algorithms, Hopper combines its world-class travel agency offering with proprietary fintech products to bring transparency, flexibility and savings to travelers globally. We have developed several unique fintech solutions that address everything from pricing volatility to trip disruptions – helping people travel better and save more on their trips. The Hopper platform serves hundreds of millions of travelers globally and c