Senior Backend Developer (Python)
Posted Updated
Description
- 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
- 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
- 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
- Software engineering discipline. Testing, code review, Git, and the habits of someone who builds things that others can maintain
- C#: You will also work with the existing platform, you need to write quality, clean, testable code in C#
- Familiarity with AWS services (Lambda, API Gateway, S3) or equivalent cloud infrastructure
- Experience with API specification tooling (OpenAPI/Swagger, Pydantic, etc.)
- Familiarity with constraint-solving tools such as OR-Tools, PuLP, or equivalent in a real-world setting
- Exposure to Python packaging, dependency management, and CI pipelines
- Experience in a B2B SaaS, telecom, or logistics context where algorithmic correctness has real commercial stakes
- Comfort with performance profiling and optimization in Python