Senior Backend Engineer - Freelance

Senior Backend Engineer - Freelance Join us We usually respond within two weeks We are bsport. The place to be! bsport is an all-in-one platform combining boutique fitness and advanced technology. Our platform helps our partners manage their bookings, payroll, marketing and more, to streamline operations and boost their commercial success. Since we launched in 2019, we have already achieved the following: We’ve built a community of over 7 million users 🤝 In December 2024 we have finalised the biggest Series B ( €30 million )🏆 Grown our team to more than 200 employees 🚀 Experienced strong worldwide growth ( 75% YoY ) and rapid geographical expansion ( +20 countries ) We’re continuing to grow to become the #1 tech partner for boutique studios in Europe and the rest of the world! Join us to write the next chapter of your career! About the role You'll take ownership of the backend behind a set of new member-facing gamification and engagement features in our white-labeled, premium Branded (mobile) App, shipping capabilities to 500k+ MAUs and driving growth for our B2B clients. This is greenfield, high-ownership work: new services and data models built on top of a large, existing product dataset. What this mission offers? A varied, high-ownership mission at the core of the product, with direct impact in the short and medium term. A modern stack and real architectural challenges, such as new data models, event-driven systems, privacy by design. A high-growth context with an engaged team and strong engineering standards. Integrate with background/event-driven processing and notifications. Ensure everything you build is scalable, reliable, and well-tested, end-to-end. 🎯 What will be your impact Design and build new backend services and data models that power upcoming features in our mobile app. Design new relational models from the ground up: weigh architecture options, align with our Core team, and document decisions (ADRs). Build and evolve the APIs / BFF endpoints consumed by the mobile app. Work with large volumes of existing product data to power new experiences, including backfills and migrations on high-volume tables. Treat privacy and data protection (GDPR) as a first-class concern, opt-in flows, and safe multi-tenant data handling. Integrate with background/event-driven processing and notifications. Ensure everything you build is scalable, reliable, and well-tested, end-to-end. 🌟You would be great fit if you have: 5+ years of backend experience, with strong Python (Django) and PostgreSQL at scale. Genuine data-modeling depth, comfortable designing new relational models and running migrations on large, high-volume tables. You thrive in ambiguity taking ownership of greenfield systems from day one. You explore the options, capture your reasoning in ADRs, and rally adjacent teams around a shared direction. Rigorous about code quality, able to move fast without cutting corners on maintainability. Strong communication skills in English. Background in a startup or scale-up, ideally B2B SaaS. Nice to have Experience with consumer / member-facing products. Experience with security- and privacy-sensitive features (GDPR, multi-tenant data isolation); able to reason about where data can leak and design against it. Some React Native experience, to collaborate closely with our mobile engineers and occasionally contribute on the client side. 🌈🌍 Diversity is one of our most valuable assets, and we are committed to fostering an inclusive environment where everyone can contribute their best work. We welcome applicants from all backgrounds, identities, and experiences to help us build a more inclusive, equitable team. If you’re excited about this role but don’t meet every qualification, we encourage you to apply-curiosity, adaptability, and a willingness to learn are just as important to us as specific skills. What we offer We believe great work comes from happy, supported people-that’s why we offer meaningful perks designed to promote balance, growth, and connection. 💵 Attractive compensation package Competitive salary packages based on your experience and role. 💻 Work-Life harmony Hybrid model with 3 days in the office per week 🌎 Work from anywhere Enjoy up to 15 days of remote work from abroad each year. ❤️ Private health insurance We offer fully-funded Alan private health coverage so you can focus on what matters most. 💪🏽 Exclusive fitness perks Stay active with a specially discounted access to Wellhub. 🍔 Flexible remuneration Enjoy tax reductions thanks to Alan Flex 🌍 Diverse fun loving team Multicultural colleagues, after-work events, team-building & more. Departments Software Engineering Role Senior Backend Software Engineer Locations Barcelona, Passeig de Gràcia Remote status Hybrid Employment type Full-time Job Level IC4 - Senior Barcelona, Passeig de Gràcia