Software Engineer Elixir / Rust (m/k/d)

Job Description

At sonnen, we're driven by a clear goal: creating a future powered by clean, affordable energy for everyone. That's why we make our customers independent - not only from fossil fuels, but also from rising electricity costs.

The key to this independence is our intelligent, all-in-one energy system. It combines solar panels, battery storage, energy tariffs, and wallboxes - all developed and manufactured in Germany.

As the first and only provider in Germany, we also connect thousands of home batteries into one shared network: the sonnenVPP, our industry-leading virtual power plant.

In short: every day, we're working to shape the energy future. And we'd be thrilled to have you join us!

Our Virtual Power Plant is a one-of-a-kind platform to provide grid services with sonnenBatterie-systems. By connecting household battery energy storage systems to our VPP, sonnen allows its customers to participate in ancillary services such as frequency control and demand response, further enabling the renewable energy revolution.

What you will do to help drive energy transition

• Contribute to a distributed Virtual Power Plant controlling tens of thousands of home battery systems across 8 countries in real time
• Design, analyze, and improve algorithms for grid services - FCR, intraday trading, demand response, and spot optimization
• Develop algorithms that optimize energy use within individual households, balancing self-consumption and cost savings under dynamic energy prices
• Build and run simulations to model real battery behavior and validate algorithmic decisions
• Analyze data streams to monitor system health and develop new signals that add value to the VPP
• Implement protocols, backend services, and client features in a production Elixir/Rust codebase

What you will need on that journey

• Experience with Elixir, Rust, or Erlang - or strong motivation to learn. We hire at all experience levels.
• Solid foundation in algorithms and mathematics; you enjoy working through problems that don't have obvious solutions
• Comfortable reasoning about distributed systems, concurrency, or real-time constraints - or eager to develop that understanding
• Experience with functional programming (Clojure, OCaml, Haskell, Scala) or Python is a plus
• Fluent in English. German is a plus.

What you can expect at sonnen

• An atmosphere of openness, tolerance and mutual respect, where innovation is expected and encouraged
• 30-32 days annual vacation with increasing team membership
• Leasing of company (e-)bikes with up to 40% discount
• Flexible working hours and option working mobile
• Use of sports memberships (EGYM Wellpass, only €29.75/month) and discounts for other services and products
• Employee discount on our electricity tariff
• Regular team and company events
• We love dogs! You too? Feel free to bring your fellow friend to our offices

You feel we are a match? Apply now and help us to shape the energy transition together. We look forward to welcoming you to #teamsonnen!