Senior Python Back-End Developer (m/f/d)
Contract
Brussels, Belgium
24.04.2026
We are looking for a Senior Python Back-End Developer to join our client, a big EU Institution based in Brussels. The role is fully remote from any country within the European Union. No trips are supposed to be requested. The role is open only to freelancers. The visibility of the mission is 80 days initially with the possibility of being extended.
The Senior Python Back-End Developer supports the CMRE Data Management Programme, focusing on the design, development, and maintenance of scalable backend systems and APIs.
The role is centered on building core data capabilities, including:
• Data Catalogue
• Data Domain Model
• Data Sharing Workflows
• Working within an Agile environment under the guidance of a Software Architect, the developer translates architectural designs into secure, high-performance, production-grade solutions. The role requires strong ownership across the full software lifecycle—from design through deployment—along with active participation in technical decision-making and team collaboration.
Key Duties and Responsibilities
• Design, develop, and maintain backend services and APIs using Python
• Translate architectural designs into scalable, maintainable code
• Build and support data-driven systems (catalogues, models, workflows)
• Ensure performance, security, and reliability of backend applications
• Take full ownership of features from design through deployment
• Develop and execute testing strategies (unit, integration, TDD)
• Participate in code reviews and enforce coding standards
• Mentor junior developers and support team knowledge sharing
• Contribute to architectural discussions and technical design decisions
• Identify and communicate risks, blockers, and dependencies proactively
• Collaborate with cross-functional teams (DevOps, QA, frontend, architects)
• Maintain CI/CD pipelines and support automated deployment processes
• Ensure proper documentation of code, APIs, and architectural decisions
Mandatory Requirements
Experience
• Minimum 7 years of professional experience in backend software development
Technical Skills
Programming & Frameworks
• Advanced Python (async programming, type hints, packaging)
• Production experience with FastAPI and async best practices
• Strong OOP and design pattern knowledge
API Development
• REST API design (OpenAPI, versioning, pagination, error handling)
• JSON and schema validation (Pydantic, Marshmallow)
• Event-driven architectures and message brokers (e.g. Kafka, RabbitMQ)
Databases
• Strong SQL and relational database experience (PostgreSQL, SQL Server)
• Experience with NoSQL (e.g. MongoDB, Redis, Elasticsearch)
• ORM frameworks (SQLAlchemy, Django ORM)
Infrastructure & DevOps
• Docker (multi-stage builds, optimisation)
• Kubernetes basics (deployment, debugging)
• Linux administration and scripting
Software Engineering Practices
• Testing (pytest, TDD, integration testing)
• CI/CD pipelines (GitHub Actions, GitLab CI, Azure DevOps)
• Advanced Git usage (branching, merging, conflict resolution)
• Code quality tools (linting, static analysis, type checking)
Security
• Secure coding practices (OWASP Top 10)
• Authentication/authorisation (OAuth2, JWT, OpenID Connect)
• API security (rate limiting, CORS, TLS)
Architecture & Collaboration
• Understanding of microservices and distributed systems
• Ability to read and contribute to architecture diagrams (UML, C4)
• Agile methodology experience (Scrum ceremonies, backlog refinement)
• Fluent in English
Desirable Requirements
Data Management & Standards
• Experience with metadata standards (e.g. Dublin Core, ISO 19115, STANAG 2586)
• Knowledge of Semantic Web technologies (RDF, DCAT, Apache Jena)
Cloud & Platforms
• Microsoft Azure (Entra ID, DevOps, Key Vault)
• Cloud-native development and services
Observability
• Logging, monitoring, and metrics (Prometheus, Grafana)
• Distributed tracing (OpenTelemetry)
AI / Advanced Technologies
• Experience with LLM frameworks (LangChain, LlamaIndex)
• Knowledge of Retrieval-Augmented Generation (RAG) pipelines
• Familiarity with AI-assisted development tools
#LI-EE1
The Senior Python Back-End Developer supports the CMRE Data Management Programme, focusing on the design, development, and maintenance of scalable backend systems and APIs.
The role is centered on building core data capabilities, including:
• Data Catalogue
• Data Domain Model
• Data Sharing Workflows
• Working within an Agile environment under the guidance of a Software Architect, the developer translates architectural designs into secure, high-performance, production-grade solutions. The role requires strong ownership across the full software lifecycle—from design through deployment—along with active participation in technical decision-making and team collaboration.
Key Duties and Responsibilities
• Design, develop, and maintain backend services and APIs using Python
• Translate architectural designs into scalable, maintainable code
• Build and support data-driven systems (catalogues, models, workflows)
• Ensure performance, security, and reliability of backend applications
• Take full ownership of features from design through deployment
• Develop and execute testing strategies (unit, integration, TDD)
• Participate in code reviews and enforce coding standards
• Mentor junior developers and support team knowledge sharing
• Contribute to architectural discussions and technical design decisions
• Identify and communicate risks, blockers, and dependencies proactively
• Collaborate with cross-functional teams (DevOps, QA, frontend, architects)
• Maintain CI/CD pipelines and support automated deployment processes
• Ensure proper documentation of code, APIs, and architectural decisions
Mandatory Requirements
Experience
• Minimum 7 years of professional experience in backend software development
Technical Skills
Programming & Frameworks
• Advanced Python (async programming, type hints, packaging)
• Production experience with FastAPI and async best practices
• Strong OOP and design pattern knowledge
API Development
• REST API design (OpenAPI, versioning, pagination, error handling)
• JSON and schema validation (Pydantic, Marshmallow)
• Event-driven architectures and message brokers (e.g. Kafka, RabbitMQ)
Databases
• Strong SQL and relational database experience (PostgreSQL, SQL Server)
• Experience with NoSQL (e.g. MongoDB, Redis, Elasticsearch)
• ORM frameworks (SQLAlchemy, Django ORM)
Infrastructure & DevOps
• Docker (multi-stage builds, optimisation)
• Kubernetes basics (deployment, debugging)
• Linux administration and scripting
Software Engineering Practices
• Testing (pytest, TDD, integration testing)
• CI/CD pipelines (GitHub Actions, GitLab CI, Azure DevOps)
• Advanced Git usage (branching, merging, conflict resolution)
• Code quality tools (linting, static analysis, type checking)
Security
• Secure coding practices (OWASP Top 10)
• Authentication/authorisation (OAuth2, JWT, OpenID Connect)
• API security (rate limiting, CORS, TLS)
Architecture & Collaboration
• Understanding of microservices and distributed systems
• Ability to read and contribute to architecture diagrams (UML, C4)
• Agile methodology experience (Scrum ceremonies, backlog refinement)
• Fluent in English
Desirable Requirements
Data Management & Standards
• Experience with metadata standards (e.g. Dublin Core, ISO 19115, STANAG 2586)
• Knowledge of Semantic Web technologies (RDF, DCAT, Apache Jena)
Cloud & Platforms
• Microsoft Azure (Entra ID, DevOps, Key Vault)
• Cloud-native development and services
Observability
• Logging, monitoring, and metrics (Prometheus, Grafana)
• Distributed tracing (OpenTelemetry)
AI / Advanced Technologies
• Experience with LLM frameworks (LangChain, LlamaIndex)
• Knowledge of Retrieval-Augmented Generation (RAG) pipelines
• Familiarity with AI-assisted development tools
#LI-EE1