Senior Software Engineer (Rails)

At 8returns, we’re transforming one of the most frustrating, environmentally damaging, and costly aspects of e-commerce: returns. Trusted by the fastest-growing DTC names like OACE, PEGADOR, GOT BAG, and now adopted by iconic brands such as Fielmann, Tommy Hilfiger, and Reebok, we’re inventing what’s next in post-purchase. As a Backend Software Engineer at 8returns, you’ll own the systems that make our product fast, reliable, and scalable. From APIs to data models to integrations, you’ll build the foundation that turns returns chaos into margin protection. If you care about clean architecture, love shipping, and want real ownership, this is your role. Tasks Ship new backend features with Rails and PostgreSQL Design and maintain APIs that power our frontend and external integrations Improve performance, reliability, and developer experience across the stack Own core data models and workflows that merchants rely on daily Debug and fix issues quickly, but always aim to build long-term solutions Explore ways to integrate AI/automation to make systems smarter and faster Work closely with founders and PM to prioritize what matters most Requirements 3+ years building production web apps with Rails Strong database skills (PostgreSQL, schema design, query optimization) Solid understanding of backend architecture and API design You’re pragmatic — you solve problems, not just write code Comfortable with ambiguity and tradeoffs; you keep moving Autonomous. We give you problems, not solutions Bonus points if: You’ve worked in an early-stage SaaS startup or as a founder You know your way around Heroku / AWS / infrastructure basics You’ve dabbled in AI/LLMs (OpenAI, Claude, LangChain, etc.) You can jump into React/TypeScript when needed Benefits: Direct impact on millions of users Own what you build, no layers of approval Low-meetings, high-ownership culture Work directly with the founders Berlin-based, flexible hybrid setup Meaningful equity in a profitable, fast-growing company We run lean, stay profitable, and care about solving real merchant problems. Ready to build the backbone of the future of e-commerce? Let’s talk.