Senior Software Engineer (Early-Stage SaaS | .NET & React) London | On-site | Full-time | Up to £100k equity The Role A fast-growing startup is building a financial operations platform and is looking for a hands-on Senior Software Engineer. You’ll help build the product from the ground up, own key features, and have a real influence on both the technology and the direction of the platform. What You’ll Do Build new features across the backend and frontend Work with .NET and a modern JavaScript framework (React used internally) Help shape the architecture as the platform scales Work closely with founders, engineers and product teams Take ideas from concept to production What You Need Experience building software with .NET or another modern backend language Experience with JavaScript/TypeScript on the frontend Comfortable working with APIs and databases Good problem-solving skills and ability to take ownership Keen to work in a startup environment where things move fast Nice to Have (Not Essential) Cloud experience (Azure, AWS or GCP) Worked in startups or on SaaS products Understanding of financial or data-heavy systems Why Apply? High ownership and influence from day one Chance to help shape a product and engineering culture early Competitive salary meaningful equity Work with a small, ambitious team solving real-world problems