In office 3 days a weekA 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 ROLEInvestment 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 CONTRACTSDesign 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 without breaking consumers.WHAT YOU'LL BE DOING - PRODUCTION QUALITYMaintain comprehensive unit and integration tests with pytest and pytest-asyncio, and uphold code review standards.WHAT YOU'LL BE DOING - DELIVERY AND COSTDeploy and operate on AWS using EKS/ECS patterns, RDS and S3 through Jenkins quality gates.WHAT WE'RE LOOKING FOR5+ years in back-end engineering for production SaaS or platform systems.Strong Python with FastAPI or comparable frameworks, solid SQL/PostgreSQL, and the ability to work at Java/Spring service boundaries.Production AWS experience, plus confidence with Git, CI/CD and Linux.Daily use of AI coding tools such as Cursor or Claude Code, and a considered view of where they help.A degree in engineering, computer science or a related field, or equivalent experience.NICE TO HAVEJava/Spring depth alongside Python.Financial services or regulated-industry systems.The opportunity is to build the foundations of an enterprise-grade technology platform aimed at a multi-billion-dollar serviceable market, and to share in that growth.A service or API contract you evolved without breaking its consumers.A production quality, reliability or cost problem you diagnosed and improved.LOCATION & WORKING PATTERNBased at Kings Cross, London, in office 3 days a week.To understand more about what we do with your data please review our privacy policy in the privacy section of the Oscar website.
Engineer - back End Developer in London employer: Oscar
Join a dynamic and innovative software and Business Intelligence organisation in Hertford, where you'll thrive in a hybrid work environment that promotes flexibility and collaboration. As a Data Consultant, you'll enjoy a varied role with opportunities for professional growth, including managing projects from inception to deployment and engaging with a European customer base. The company fosters a supportive culture that values continuous learning and offers exposure to exciting industry events, making it an excellent employer for those seeking meaningful and rewarding work.
