At Upside, we’re not just shipping features - we’re partnering with ambitious companies across the globe to solve complex, meaningful problems through technology. We work in small, focused teams, combining engineering, product thinking, and design, to deliver outcomes, not just output.Open-source is a strategic part of our work. We build and maintain a number of open-source projects that support our clients and internal R&D. Our latest release is Enthusiast, an AI Agent framework tailored for e-commerce use cases.Role Overview:As a Backend Engineer, you will be integral to the process of building and maintaining platforms that meet the needs of our global clients. Your work will significantly support the infrastructure of the solutions directed towards clients. You'll be part of a development team, sized between 3 to 9 members, dedicated to crafting scalable and resilient backend systems. This role involves collaborating closely with both the development team and our clients, ensuring that our backend solutions are perfectly aligned with client requirements and expectations.Job requirements→ Relevant commercial experience in building web-based application (>2 years).→ Experience in at least one of Upside’s core technology stack: Ruby, Python, JavaScript or the willingness to learn based on your current skills.→ Deep understanding of end-to-end software development cycle.→ Great command of written and spoken English.Relevant technology skills:→  Experience with SQL databases.→  Experience with orchestration tools (e.g. AWS/Docker/Kubernetes).→  Solid OOP skills.→  Experience with Git, unit testing, debugging, and profiling.→  Experience with Continuous Integration and Continuous Delivery.→  Experience in creating modern APIs.→  Knowledge of frontend frameworks and tools (e.g. Vue.js, React.js) is nice to have.→  Knowledge of Node.js, JavaScript is nice to have. If you didn't find all the information you were looking for, have a look at our handbook - it covers a variety of different matters that could be important at this stage. If there's anything else we did not mention that you're interested in - share your thoughts with us [email protected]:Regular Engineer: 10 000 - 13 600 PLN net + VAT Regular+ Engineer: 14 800 - 19 300 PLN net + VATIncluding additional days off and paid bank holidays.Location:Office in Kraków, hybrid, fully remotely.