Backend Engineer Location: Kings Cross, London Salary: £85,000-105,000 Contract: Permanent Working pattern: In office 3 days a week A newly formed software venture backed by an established global investment-services business is hiring a Backend Engineer to build the platform its product runs on. You''ll design multi-tenant data and workflow services in Python and FastAPI and own the integration layer between a Java/Spring core and Python AI services. This is one of nine engineering hires across front-end and back-end. THE ROLE Investment professionals need APIs and workflows that respect permissions, keep an audit trail and fail safely when an AI result can''t be trusted. You''ll build the services behind that. Report to the Head of Engineering as part of the UK core team. Build multi-tenant data and workflow services, plus the integration layer between the Java/Spring core and the Python AI services. Ship through disciplined CI/CD alongside the India-based delivery organisation. Combine service design with the production constraints of demanding enterprise users. Join a nine-person engineering cohort being hired across front-end and back-end. WHAT YOU''LL BE DOING - SERVICES AND CONTRACTS Design REST and asynchronous services in Python 3.11+ and FastAPI. Work at Java/Spring boundaries with PostgreSQL and async SQLAlchemy persistence. Implement tenant isolation, context, role-based access and configuration. Version and evolve contracts between core and AI services ..... full job details .....