Gesloten zzp vacatures Sliedrecht

Location: Rotterdam (hybrid, at least 50% on-site)
Hours: 40 per week
Start date: 29 September 2025
Application deadline: 12 September 2025
Note: Freelance / ZZP candidates cannot be considered for this role.

The energy transition is placing unprecedented demands on our electricity grid. As a Senior Python Developer, you will contribute directly to solving this challenge by working on the development of the Flex Toolkit – an innovative tool that optimizes grid capacity, enables accurate capacity calculations, and supports flexible contract management. The outcome? Greater insights, improved decision-making, and reduced congestion.

In this role, you will combine technically challenging work with social impact. You’ll collaborate closely with multiple teams, gather user feedback, and ensure seamless integration of the Flex Toolkit with other key systems. You will also play a coaching role for fellow developers, helping them grow and fostering a culture of continuous improvement.

• Develop and enhance the Flex Toolkit using Python, with a focus on GUI and tool development.

• Work with stakeholders and cross‑functional teams to optimize test and development processes.

• Translate user feedback into functional improvements.

• Ensure smooth integration with surrounding systems (e.g., PowerFactory, Setiam, SAP).

• Actively coach, support, and inspire other developers within the team.

• Higher professional education (HBO) level of working and thinking, preferably with a degree in Computer Science.

• At least 5 years of experience as a Python Developer, with strong skills in GUI/tool development.

• Hands‑on experience with SQL, Git, Azure Cloud, Databricks, and CI/CD pipelines.

• Familiarity with JavaScript frameworks such as React, Vue.js, and/or Angular is a strong plus.

• Experience with Agile/Scrum ways of working.

• Strong communication skills and the ability to work effectively in a team.

• Proficiency in English; willingness to learn Dutch is welcomed.

You will join the Agile Release Train (ART) Forecasting & Capacity Management, a team consisting of a Product Owner, Scrum Master, Business Analyst, and three Developers. The team enjoys a high degree of autonomy while working within clear architectural frameworks and collaborating with other teams across the organization.

Every quarter, you will participate in Big Room Planning sessions – two-day events based on the SAFe methodology – where IT and business colleagues align and plan together. This is where your contributions help shape the future of energy management and capacity planning.