Senior Backend Developer (API Design & Development) for NATO

Would you like to join the leading international intergovernmental organization? We are seeking a Senior Python Backend Developer to design, build, and operate scalable services and data pipelines that power maritime geospatial and temporal analytics across the platform. You will develop production-grade APIs and microservices, integrate with Neo4j for graph-centric use cases, and leverage Databricks for data engineering and ML workflows. You will collaborate closely with architecture, data engineering, and product to translate domain models into clean, testable code using Domain-Driven Design. Expect to define clear bounded contexts, align contracts and schemas, and ensure services reflect the ubiquitous language of the domain. This is a hands-on engineering role with strong ownership. You will lead features end-to-end—from technical discovery and design through implementation, testing, deployment, and runtime monitoring—prioritizing reliability, performance, and security. You will participate in code reviews, mentor peers, contribute to architectural decisions, and proactively surface technical risks and trade-offs. Clear, timely communication on progress and blockers is essential. Essential Qualifications & Experience: Back-End Development & Programming Python: Advanced proficiency; clean, idiomatic code; familiarity with the ecosystem (virtual environments, packaging, type hints, async/await) Frameworks: Production experience with FastAPI famwork and async best practices OOP & design patterns: Solid object-oriented design skills; familiarity with common design patterns (factory, strategy, repository, dependency injection) Domain-Driven Design (DDD): Strong practical experience applying DDD principles, including bounded contexts, aggregates, repositories, domain services, ubiquitous language, and event-driven domain modelling Performance: Profiling, caching strategies, connection pooling, async processing, background task queues (Celery, Dramatiq, or equivalent) API Design & Development RESTful APIs: Resource modelling, versioning, error handling, pagination, OpenAPI / Swagger documentation Data formats: JSON, JSON Schema validation; familiarity with serialisation libraries (Pydantic, Marshmallow) Event-driven systems: Message brokers (Kafka, MQTT, Azure Event Hubs etc.), pub/sub patterns, async task processing Databases & Data Persistence Relational databases: Strong SQL skills; experience with PostgreSQL and/or SQL Server; schema design, indexing, query optimisation, migrations Graph databases: Strong hands-on experience designing and working with Neo4j graph databases, including Cypher query optimisation and graph data modelling Geospatial & temporal data: Strong experience modelling, processing, querying, and extending geospatial and temporal datasets and services; familiarity with spatial indexing, time-series data, and geospatial standards/tools Containerisation & Linux Docker: Writing Dockerfiles (multi-stage builds), Docker Compose for local development, image optimisation Kubernetes: Basic understanding of K8s concepts (pods, services, deployments, ConfigMaps) for deploying and debugging applications Linux: Comfortable with the command line; shell scripting, process management, file permissions, networking basics Software Engineering Practices Testing: TDD, unit testing (pytest), integration testing, mocking, code coverage; awareness of contract testing CI/CD: Building and maintaining pipelines (GitHub Actions, GitLab CI, Azure DevOps, or equivalent); automated linting, testing, and deployment Version control: Advanced Git usage, branching strategies (GitFlow, trunk-based), pull/merge requests, rebasing, conflict resolution Code quality: Static analysis, linting (Ruff, flake8, mypy), code review best practices, documentation (docstrings, ADRs) Security Secure coding: OWASP Top 10 awareness, input validation, output encoding, secrets management Authentication & authorisation: OAuth 2.0, OpenID Connect, JWT; experience integrating with identity providers (Keycloak, Entra ID, or equivalent) API security: Rate limiting, CORS, TLS, API key management Architecture Awareness & Collaboration Architecture literacy: Ability to read and contribute to architectural documentation (C4, UML); understanding of microservices, event-driven, and layered patterns Agile: Active participation in sprint ceremonies, backlog refinement, estimation, and retrospectives Communication: Clear reporting of progress and blockers; collaboration with architects, front-end developers, QA, DevOps, and UX designers English proficiency: Excellent written and spoken English in a professional/international context 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.