Senior Backend Developer (Python Backend) for NATO

Would you like to join the leading international intergovernmental organization? We are looking for a senior Python Backend contractor to support the modernization of existing applications as part of a broader platform transition. This is a highly hands-on role: the selected contractor must have strong practical experience and be able to contribute from day 1 with minimal ramp-up. The main focus of this role is to refactor existing Python applications with minimal intervention to support the gradual decomposition of a monolith into a set of decoupled services, while ensuring that configuration and settings are fully environment-based. This is a delivery-focused role, not a greenfield rewrite or architecture-only position. We are looking for an engineer who can assess the existing codebase quickly, identify pragmatic refactoring opportunities, and implement them directly. Important: we will only consider candidates whose primary professional experience is as a Python Backend Engineer. Profiles coming mainly from adjacent roles with only partial backend exposure will not be considered Key responsibilities: Refactor existing Python backend applications to support the decomposition of a monolith into smaller, decoupled services. Identify pragmatic, low-impact changes that improve modularity and separation of concerns without unnecessary redesign. Ensure application configuration and settings are environment-based and suitable for deployment across multiple environments. Develop and maintain production-grade backend services and APIs in Python with focus on maintainability, reliability, and security. Support the transition of applications toward containerized and automated deployment models, working closely with DevSecOps and platform engineers. Improve code quality, testing, troubleshooting, and documentation to enable safe incremental change. Troubleshoot and resolve functional, integration, and performance issues in existing backend services. Document implemented changes and contribute to good backend engineering practices across the team. Essential Qualifications & Experience: 7+ years of professional experience in backend software development, with Python backend engineering as the main professional focus. Strong recent hands-on experience in Python backend development. Proven experience building and maintaining production backend services and APIs. Proven experience working in existing or legacy codebases and performing incremental refactoring. Practical experience supporting the decomposition of monolithic applications into smaller, decoupled services. Strong understanding of environment-based configuration, backend architecture, API design, and database design. Good understanding of integration patterns, service boundaries, and maintainable backend design. Familiarity with CI/CD practices, Git workflows, code reviews, and Agile/Scrum delivery. Good understanding of secure coding practices and writing maintainable, well-tested code. Strong analytical, debugging, communication, and documentation skills. Experience with Docker and Kubernetes-based deployments. Experience with message queues, event-driven architectures, or caching strategies. Experience in cloud or hybrid environments. Good spoken and written English. If you've read the description and feel this role is a great match, we'd love to hear from you! Click "Apply for this job" to be directed to a brief questionnaire. It should only take a few moments to complete, and we'll be in touch promptly if your experience aligns with our needs.