Senior Software Engineer – AI Team (.NET/C#) We’re partnering with a fast-growing fintech and payments business that’s building intelligent, AI-powered software used by thousands of businesses across the UK. They’re now looking for a Senior Software Engineer to join their AI team, focused on developing production-grade AI systems that automate complex financial and accounting workflows — not just chatbots. You’ll work in a small, autonomous squad with full ownership across the stack, from scalable back-end services to intuitive front-end interfaces, collaborating closely with the AI platform team to bring LLM-powered features into core products. What you’ll be doing Architect and build scalable, secure AI-powered applications Design performant back-end services in C# / .NET, integrating with AI systems Develop user-friendly front-end interfaces using Blazor or React/Vue/Angular Lead technical direction, mentor engineers, and promote best practices Collaborate with AI teams to design and deliver real production features What you’ll need Proven full-stack experience delivering production web applications Hands-on experience with LLMs / GenAI / ML in production Strong background in C#, .NET, REST APIs, and cloud platforms (Azure, AWS, or GCP) Agile mindset with focus on testing, observability, and secure delivery Excellent communication and cross-functional collaboration skills Nice to have Experience with vector databases, RAG systems, or multi-agent AI Python skills for AI/ML development Familiarity with MLOps, Langfuse, or LiteLLM Background in fintech, SaaS, or payments software Join a forward-thinking fintech where you’ll have the freedom to innovate, influence technical direction, and build AI systems that genuinely impact users.