London - 5 Days On Site50% Backend. 50% Frontend. 100% Technical Ownership.Can you build the backend, own the frontend and confidently explain every architectural decision in between?We''re looking for a genuinely strong Senior Software Engineer who loves building complete solutions, not just working on isolated tickets.This is a hands-on, evenly balanced full-stack engineering role combining production Python development with modern TypeScript and React.You''ll be working on technically challenging products, taking ownership of features and solutions from initial design through to production, while helping shape how the wider platform evolves.We want someone who thinks like an engineer, not just a coder. Someone who understands what happens when systems scale, when services fail, when concurrency becomes an issue and when architectural decisions have long-term consequences. What will you be building?Designing, developing and owning end-to-end software solutions using Python and TypeScript.Building robust backend services and APIs using Python, ideally FastAPI.Creating responsive, maintainable frontend applications using React and TypeScript.Developing and integrating services that connect modern applications with AI-powered capabilities.Designing solutions involving APIs, databases, event-driven architectures and distributed systems.Working with SQL databases, ORMs and efficient data access patterns.Making architectural decisions around scalability, performance, reliability ..... full job details .....