Senior Backend Engineer

We Are Sparta Sparta is the AI leader for commodity trading, home to Leonidas AI, the first operating system for oil and commodity traders. Backed by $42 million in Series B funding led by One Peak, with participation from returning investors FirstMark and Singular, the same investors behind AI leaders like Legora, Dataiku, and Synthesia. Most companies are building a chatbot on top of data. We've built an agent with an actual reasoning layer, grounded in years of proprietary market data and in-house trading expertise nobody else has. We're scaling fast, and it's an exciting time to join. From independents to multinationals, the world's leading commodity teams use Sparta and Leonidas AI to move faster, trade smarter, and stay ahead of the market. At Sparta, you'll be trusted to take ownership, backed by a team who wants you to succeed. AI is how we build here, not just what we sell. Good ideas move fast, and yours could go from staging to production in a couple of hours, whatever department you're in. You'll be challenged, supported, and given room to grow, building the AI that's changing how commodity trading gets done. Your work has reach. From shaping Leonidas AI, to powering smarter decisions for traders around the world, to changing how commodity trading is done. And because we're growing fast, you'll accelerate your career with a level of ownership and impact you simply won't get at bigger, slower-moving companies. At Sparta, we’re on a mission to build the next generation of commodity trading platforms - replacing the fragmented tools that traders typically rely on with a single, powerful dashboard. Our product is a data-driven platform that aggregates real-time feeds from across the commodities domain, transforming them into intuitive, actionable visualisations within one unified interface. Users can explore pre-built data views or define their own custom formulas to create tailored insights. To deliver on this vision, our engineers tackle real distributed systems problems on a daily basis, where designing for reliability and performance at scale is essential to a seamless user experience. As we unlock the next level of scale, those problems get harder and more interesting. This role is for an engineer who wants to own meaningful parts of that system now, and grow into the technical decisions that shape it. We’re looking for people who thrive in an empowered environment - engineers who are comfortable being given problems to solve rather than solutions to implement. You should enjoy working at pace, value autonomy, and prefer to ask for forgiveness rather than permission. You won’t be handed tickets. You’ll be handed context, and trusted to work out the right thing to build. Whereas Sparta is a remote-first company, for this role we’re looking for someone who values a hybrid working style, which in a typical week could involve spending a couple of days in the office - with flexibility built in. WHAT YOU’LL BE DOING: • Design, build and maintain the backend services behind our real-time and analytical data processing. • Own features end to end, from shaping the approach to running them in production. • Optimise pipelines and services for low latency, high throughput and scale. • Work with engineers, product and stakeholders to stay aligned on direction. • Contribute to design reviews with a clear view on the trade-offs. • Keep your services healthy - observability, feedback loops, incident response. • Raise the bar around you through code review, pairing and knowledge sharing. ABOUT YOU: • 4+ years as a software engineer, with production systems you’ve built and supported. • High ownership tendencies • Experience in a product-focused organisation, working cross-functionally. • Comfortable across multiple