Job offer: apply now as Java Developer!

Ready to develop software for renewable energy systems?

We have the job for you!


At Vela Solaris AG we are committed to making the planning of innovative energy systems simple and reliable! With our in-house developed software Polysun, we are world leaders in the digital simulation of energy systems for buildings. Renowned engineering companies, manufacturers and universities in over 40 countries rely on Polysun. Our customers realize efficient and sustainable solutions by cleverly linking all commercially available technologies – from PV, heat pumps, battery systems and energy management systems and many more.

To strengthen our software development team, we are filling a position as:

Java Developer, 80%-100%

Your tasks:

The further development of the simulation software Polysun is your main task: Here you can optimally contribute your skills in software programming and your interest in renewable technologies.

  • Together with your team colleagues you will define the requirements for the further development of Polysun and implement them directly. In doing so, you will work your way into the dynamic time step simulation of Polysun and continuously develop new technological features.
  • Improving the usability by optimizing the graphical user interface is also part of your tasks.
  • You ensure the software quality in joint code reviews.
  • Due to your growing expertise in the Polysun program code, you are the team’s contact person for 3rd level customer inquiries.
  • As part of the development team, you ensure that the software architecture is robust and carry out refactorings.

Your profile:

You are passionate about developing clean modular code and have several years of experience in software development with Java. You have a university degree in computer science, electrical engineering, environmental and natural sciences or a comparable education. You have a keen interest in physical processes and have ideally already developed software in the field of renewable energy systems (e.g. photovoltaics, battery storage, thermal energy systems). It is an advantage if you already have knowledge of relational databases, SQL queries, Swing, git, gradle, Jenkins, Python and Docker/ Docker Compose. Being part of a team is important to you and you are happy to share your knowledge and learn from others. You are fluent in German and English.

Our offer:

A top team is waiting for you. We support you with questions, are helpful and very competent.  You will constantly learn new things and take on extremely exciting tasks at the pulse of the future in the energy, IT and construction industries. Freedom of design and creativity are important to us – we will ensure that you are given the necessary space for this. We take the time to train you on the job. We support you in your wishes for continuous development. With us you work in a modern working environment. You decide whether you use our central office space in Winterthur or work from your home office and also benefit from flexible working hours.

Your next step:

Does our job advertisement appeal to you? Then we look forward to receiving your application! Please send your application documents by e-mail to Urs Stöckli,