Senior Software Engineer - Kotlin

Senior Software Engineer - Kotlin £550-£650 per day | Outside IR35 Hybrid | London (3 days onsite) A leading UK financial services organisation is seeking a Senior Software Engineer to play a central role in a large-scale platform transformation programme. The business is rebuilding a critical part of its digital infrastructure to support a broad range of transaction methods and channels across both in-person and digital environments. This is hands-on Back End engineering at scale, with real ownership and direct exposure to architecture decisions from day one. Key Responsibilities as a Senior Software Engineer: Design and build Kotlin Back End services for a new payments platform Own the architecture and design of key components, taking high-level requirements and turning them into structured, deliverable backlogs Write clean, well-tested, production-ready code that the team can rely on Work closely with Product and Engineering to break down complex problems and ship impactful features Bring fresh thinking to existing approaches and propose improvements where you see them Support team leadership across delivery, code quality, and technical decision-making Contribute to technical hiring, helping to assess and attract strong engineering talent Skills andamp; Key Requirements: Strong commercial Kotlin experience for Back End development, ideally within payments or financial services Domain expertise in payment gateway systems or payments infrastructure Comfortable with React. ..... full job details .....