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.TasksShip new backend features with Rails and PostgreSQLDesign and maintain APIs that power our frontend and external integrationsImprove performance, reliability, and developer experience across the stackOwn core data models and workflows that merchants rely on dailyDebug and fix issues quickly, but always aim to build long-term solutionsExplore ways to integrate AI/automation to make systems smarter and fasterWork closely with founders and PM to prioritize what matters mostRequirements3+ years building production web apps with RailsStrong database skills (PostgreSQL, schema design, query optimization)Solid understanding of backend architecture and API designYou’re pragmatic — you solve problems, not just write codeComfortable with ambiguity and tradeoffs; you keep movingAutonomous. We give you problems, not solutionsBonus points if:You’ve worked in an early-stage SaaS startup or as a founderYou know your way around Heroku / AWS / infrastructure basicsYou’ve dabbled in AI/LLMs (OpenAI, Claude, LangChain, etc.)You can jump into React/TypeScript when neededBenefits:Direct impact on millions of usersOwn what you build, no layers of approvalLow-meetings, high-ownership cultureWork directly with the foundersBerlin-based, flexible hybrid setupMeaningful equity in a profitable, fast-growing companyWe 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.