Freelance Senior Python Developer

I’m currently supporting a leading organisation in the energy sector that is looking for an experienced Freelance Senior Python Developer to join its software development team in Brussels.

The organisation plays a key role in maintaining and developing critical energy infrastructure across Belgium and Europe and continues to invest heavily in digitalisation, monitoring platforms and reliable software solutions.

As a Senior Python Developer , you will contribute to the architecture, development and maintenance of business-critical applications supporting the organisation’s internal monitoring platform.

The platform is responsible for monitoring the health and availability of live applications through automated synthetic checks, log monitoring and alerting mechanisms. The core monitoring and alerting engines are developed in Python, alongside several supporting monitoring scripts and services.

You will work closely with software developers, Product Owners, Business Analysts, Data Engineers, Architects, IT Operations and other technical stakeholders.

Responsibilities

• Develop, maintain and optimise Python-based applications and backend services.
• Contribute to the evolution of an internal application monitoring and alerting platform.
• Develop and maintain monitoring scripts, synthetic checks and log-based monitoring solutions.
• Collaborate with stakeholders to translate requirements into technical solutions.
• Design and build reliable, scalable and maintainable backend services.
• Work with service-based and event-driven architectures.
• Troubleshoot and resolve complex application and production issues.
• Implement software engineering best practices around testing, security and code quality.
• Contribute to automated testing and CI/CD pipelines.
• Work closely with DevOps and Data Engineering teams on integrations and deployments.
• Conduct code reviews and provide technical guidance to other developers.
• Support refactoring and modernisation of existing and legacy applications.
• Ensure solutions meet the security requirements associated with business-critical infrastructure.

Profile

We are looking for an experienced Python Developer with a strong backend engineering background and experience building reliable production applications.

Core requirements

• 6+ years of professional software development experience.
• 3+ years of hands-on Python development experience.
• Experience with FastAPI or similar Python frameworks.
• Experience with Pydantic or similar data-validation libraries.
• Strong experience with AsyncIO / asynchronous Python development .
• Good knowledge of SQL .
• Experience working with PostgreSQL, Microsoft SQL Server or similar relational databases .
• Experience with RabbitMQ or comparable messaging technologies.
• Strong understanding of service-based architectures and event-driven systems.
• Good knowledge of software design patterns, data structures and algorithms.
• Experience with automated testing frameworks.
• Understanding of CI/CD and modern software development practices.
• Experience troubleshooting complex production applications.
• Strong understanding of application security and secure software development.
• Ability to work with legacy code and contribute to refactoring initiatives.
• Experience working within Agile development environments.
• Strong communication and stakeholder-management skills.
• Ability to mentor developers and provide technical guidance.
• Bachelor’s or Master’s degree in IT, Computer Science, Software Engineering or a related technical field.
• Good level of Dutch and/or French combined with English .

Nice to have

Experience with one or more of the following would be considered an advantage:

• Docker and containerised applications.
• NoSQL databases.
• Selenium or other automated testing frameworks.
• Application monitoring and observability platforms.
• Experience working within the energy, utilities or critical infrastructure sector.

You do not need experience with every technology listed above. The strongest candidates will bring solid Python backend engineering experience , combined with experience working on reliable, business-critical applications.