Job offer: apply now as API 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. Based on the Polysun API, we enable our customers to create future-oriented web applications in the field of energy system simulation in the cloud.

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

API Developer, 80%-100%

Your tasks:

The further development of the Polysun API is your main task! Here you can optimally apply your skills in software programming and your interest in renewable technologies.

  • Together with your teammates in the development you will define the requirements for the further development of the Polysun API and implement them directly.
  • Due to your expertise in the area of API, you are directly involved in customer projects and implement customer requirements.
  • You ensure the software quality in joint code reviews.
  • In the area of operations, you will work together with the team to ensure that the Polysun API is available securely and reliably.

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 or college degree in computer science or as a software engineer or a comparable education. You have extensive experience in the development of web applications, preferably in the backend area. Ideally, you already have knowledge in one or more of the following areas:

  • API design
  • OpenAPI/Swagger
  • Spring
  • Jackson, Jersey
  • Relational databases, SQL queries, etc.
  • AWS EC2 Cloud Computing
  • Unix/Linux
  • Git
  • Gradle
  • Jenkins
  • Docker, Docker Compose, Docker Swarm

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,