Full Stack Developer (Freelance) - 12 Months - Brussels Belgium

Where Builders Build the Future

At RELYzIT Talent, we don’t recruit — we build. We unite the top 2% of builders — engineers, architects, creators — into a movement across Europe and the GCC. Vetted through our VECTOR7™ Signal Stack, you’re not just hired, you’re chosen. This is more than work. This is where builders build the future.

About the Role

We are seeking a Senior Full Stack Developer (Freelance) to join our client’s innovation-driven team for a 12-month mission. This is your opportunity to architect and deliver high-impact data and risk infrastructure solutions that will shape the future of B2B trade. You’ll be at the heart of a collaborative, entrepreneurial environment, driving technical excellence and co-creating the next generation of digital trade platforms.

Why This Role Matters

Our client is on a mission to recode B2B trade for the digital era, empowering businesses with smarter, more fluid, and risk-savvy solutions. As a Full Stack Developer, you will be instrumental in building and scaling the core technology that underpins this transformation. Your work will directly impact the success of new ventures, enabling innovation, growth, and resilience in global trade ecosystems.

Key Responsibilities

• Lead the technical build of applications and reusable components, including APIs, user experience, front and backend systems, and data platforms, in close collaboration with IT leadership and enterprise architects.
• Act as a senior advisor, defining the best technologies, tools, and architectures for each project and venture.
• Partner with stakeholders to maximize the impact of new ventures and solutions.
• Drive technical benchmarks and deliver innovative solutions across web and API architectures.
• Implement and document best practices to ensure sustainable scalability and craftsmanship in all code produced.
• Maintain and enhance Python and other non-OutSystems applications, including monitoring, troubleshooting, and deploying updates.
• Oversee the maintenance of development, testing, and production environments.
• Develop new features and onboard new clients, ensuring robust testing and documentation.
• Collaborate closely with stakeholders to review and maintain comprehensive test collections.
• Conduct systematic peer code reviews to uphold high-quality deliverables and foster a culture of knowledge sharing.

Technical Skills

• Expert-level proficiency in Python
• Expertise in Google Cloud Platform
• Advanced experience with SQLModel and Pydantic
• Proven track record as a full stack developer in startup or high-growth environments
• Strong execution across both frontend and backend environments
• Experience with data architecture is a plus
• Understanding of B2B trade is advantageous; knowledge of trade credit insurance is a bonus

Language Proficiency

• English: Full professional proficiency required
• Dutch or French: Nice to have

Other Requirements

• Freelance position with a 12-month project duration
• Hybrid work model: Brussels-based with remote flexibility
• Ability to work independently and deliver consistent, high-quality results without micromanagement
• Strong sense of ownership, integrity, and a collaborative, team-first mindset
• Structured self-starter with an 80/20 approach and a drive for impact
• Willingness to travel up to 5% of the time (all travel fully expensed)
• Project managed via ProUnity platform; monthly timesheets and invoicing required

VECTOR7™ Signal Stack Vetting

All candidates are rigorously vetted through our VECTOR7™ Signal Stack, ensuring only the most capable, impact-driven builders join our movement. You’re not just applying — you’re stepping up to be chosen.

Ready to build the future? Upload your CV now and join the movement.

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