Senior Backend Engineer

Senior Backend Engineer Help us build a more efficient and sustainable future We build software for the energy system. Helicon is a software engineering company specialized in energy. We work with energy companies, technology companies, and industrial customers to build the systems that connect, understand, and control the physical world. That means everything from APIs and integrations to data platforms, optimization systems, and applications handling thousands of connected assets and millions of measurements. Now we're looking for a Senior Backend Engineer who wants to build those systems with us. The challenge The energy system is becoming increasingly software-defined. Batteries, buildings, heat pumps, EV chargers, solar panels, meters, and entire energy plants are being connected and need to exchange data, make decisions, and interact with increasingly complex energy markets. That creates some genuinely interesting engineering problems. How do you reliably ingest data from thousands of assets and systems that were never designed to talk to each other? How do you build APIs and services that remain understandable as the system grows? How do you process large amounts of time-series data and turn it into something useful in real time? And how do you build software that customers can trust when it starts controlling physical equipment? These are the kinds of problems you'll work on at Helicon. We've previously built systems connecting more than 15,000 buildings and 30,000 sensors, software for optimizing energy assets, and digital twins for complex energy systems. There's plenty left to build. What you'll do You'll spend most of your time building software. Depending on the project, that might mean: Designing and building backend services, APIs and integrations. Building systems for ingesting and processing large amounts of energy and time-series data. Connecting cloud software with devices, industrial systems and third-party platforms. Designing data models and distributed architectures. Building services for forecasting, optimization and control. Taking a problem from a conversation with a customer all the way to running software in production. Making architectural decisions without turning every decision into an architecture project. Reviewing code and helping other engineers become better. Taking technical leadership of a project or small engineering team when needed. We expect senior engineers to take ownership beyond their own tickets. If something doesn't make sense, question it. If there's a simpler solution, suggest it. If something should be fixed, fix it. You might like working here if You genuinely enjoy software engineering. You're comfortable moving between understanding the customer's problem, sketching an architecture, digging through an unfamiliar API, and writing the code that ultimately solves it. You care about good engineering, but don't confuse complexity with quality. You know that sometimes the right solution is a carefully designed distributed system, and sometimes it's a straightforward service with a database. You like autonomy, short decision paths, and seeing what you build being used in the real world. And you probably get slightly annoyed when a meeting could have been a Slack message. What we're looking for We care more about engineering ability than matching an exact technology checklist. But you'll probably have: 5+ years of professional software development experience Strong backend development skills, preferably with Python Experience designing APIs, integrations, and backend services Experience with relational databases and data modelling Experience with AWS, Azure, or GCP Good understanding of Docker, Git, and CI/CD Experience designing and operating production systems The ability to reason about architecture, performance, reliability and maintainability The ability to communicate technical decisions clearly Professional proficiency in Swedish and English Experience as a Tech Lead, Lead Developer, or senior engineer with significant technical ownership is valuable, but having held a particular title isn't important. Even better if you've worked with Energy, IoT, or connected products Event-driven or distributed systems Large-scale time-series data Kafka Kubernetes TimescaleDB, PostgreSQL, or similar technologies Databricks, Spark or Airflow Optimization, forecasting, or machine learning Industrial systems, edge computing, or OT/IT integrations You definitely don't need to know all of these. How we think about engineering Ship useful things. Software creates value when someone uses it. Keep it simple. Complexity has to earn its place. Own the problem. Don't just implement requirements. Understand what we're actually trying to achieve. Use the best tool for the job. We're not interested in technology for technology's sake. AI is part of modern software engineering. We expect our engineers to use modern AI tools where they make them faster and better, while still understanding the systems and code they build. Leave things better than you found them. Good engineering compounds. We want every project to improve the way we build the next one. Why Helicon? Because there aren't many places where a backend engineer gets to work with problems spanning cloud software, large-scale data, physical infrastructure, and the energy system. We're small enough that good engineers have a real influence on how things are built. You'll work alongside experienced engineers and data scientists, have significant technical autonomy, and get close to both the customer and the actual problem. And you'll get to build software where changing a few lines of code can ultimately change how a building, battery, or energy system behaves in the physical world. That's pretty cool. Department Engineering Role Backend Developer Locations Stockholm Remote status Hybrid Stockholm About Helicon Technologies At Helicon we build digital products that matter. As a digital product development and innovation agency specializing in cleantech, we partner with forward-thinking businesses to create breakthrough products, platforms and capabilities that drive sustainability and efficiency. Our journey has taken us from developing one of Sweden’s largest virtual power plants by connecting more than 15,000 buildings, to using AI to optimize energy, water and resource management worldwide. We have also helped launch award winning cleantech startups and SaaS solutions for the energy sector. We measure success not only by the results we deliver to our customers but also by the real world sustainability gains our solutions create. When clients tell us that our work helped shut down a coal and oil power plant, integrate more renewables into their portfolio or cut 36,000 tons of CO₂ emissions annually, we take immense pride in that. What drives us is a shared passion for solving complex challenges through strategy, design, engineering and data science. At Helicon speed, curiosity, collaboration and continuous learning are at the heart of how we work. If you are passionate about technology and want to make a positive impact on the planet, you will feel at home here. Founded in 2015 Co-workers 40 Applicant tracking system by Teamtailor