Senior Backend Developer, Expereo

• Advanced Python — non-negotiable. Clean, tested, reusable code. Not just scripts that happen to work
• API design and implementation. Designing and maintaining REST APIs with clear contracts, versioning, and proper error handling
• Software engineering discipline. Testing, code review, Git, and the habits of someone who builds things that others can maintain
• Ability to work in a mixed-language codebase. The existing platform is Python/C#. You need to be comfortable reading it and understanding the integration points

Desirable

• We are looking for a Backend Developer to join the Supplier onboarding and Quote Management teams and work directly on the computational core of our platform
• You will write Python and/or dotnet every day
• You will work on an existing Python/C# backend and create new services
• You will work on solving real-world business problems, like creating a constraint optimization engine, working on integrations with our partners and creating and maintaining internal tools
• You will work directly with the innovation and commercial teams
• This role is also designed with growth in mind
• The knowledge and context you build here — deep familiarity with the platform, the commercial logic, and the constraints of the business — make this a natural stepping stone toward a technical execution role, potentially supporting a commercial STO (single thread owner) function as the platform scales
• Implement and maintain business logic for the quote engine, partner integrations and internal services: supplier selection, service bundling, routing rules, product validation …
• Explore, document and integrate heterogeneous external data sources necessary to the execution of business logic
• Ensure all outputs are auditable, and explainable to commercial stakeholders — we don’t build black boxes
• Validate model outputs against historical data; measure and report on prediction reliability
• Optimize the operational value of the integrations with our partners
• Define contracts, manage versioning, and ensure downstream consumers are never broken silently
• Write clear, well-documented API interfaces with explicit input/output contracts and error handling
• Coordinate with the Platform engineer on service integration and ensure clean separation of concerns between components
• Maintain API documentation as a living artifact, not an afterthought
• Refactor and clean up existing Python/C# code: reduce complexity, increase testability, and bring the codebase up to production engineering standards
• Write unit and integration tests that provide real confidence — not just coverage numbers
• Apply Git, code review, and CI practices to all work. Code lives in a repository, goes through review, and is reproducible without intervention
• Document non-obvious logic thoroughly so knowledge is transferable
• Partner with the Commercial teams, Quote Engine lead Platform engineer — this is collaborative work, not ticket execution
• Participate in sprint reviews, propose approaches, and flag risks early