Senior Backend Developer
Organization: Palta (Simple / Zing / Lovi)
Location: Poland
Zing Coach is the world’s first AI Fitness Personal Trainer, revolutionising the way people approach health and wellness. Four years ago, we set out to replace traditional PT sessions with smart, personalised, motivating guidance powered by AI. We’re not just another app – we’re a movement, on a mission to help everyone reach their full physical and mental potential.We are looking for a Senior Backend Engineer to build and evolve backend services that power the Zing Coach product. This is a hands-on individual contributor role focused on shipping high-quality backend code, improving existing systems and approaches, and taking responsibility for production behaviour.ResponsibilitiesBackend feature developmentDesign and implement backend features supporting core product experiencesTake work from ideation through deployment and production supportDesign backend-first architecture used by mobile clients and internal servicesAI-backed product functionalityIntegrate backend with LLM-powered and ML-based systemsHandle latency, failure modes, and operational concerns around AI dependenciesSystem improvement and scalingImprove performance, scalability and reliability of existing backend servicesWork with relational databases: schemas, queries, migrations, and performance issuesCollaborate closely with mobile, ML, and product managers to deliver features end-to-endWhat we expect that you haveMust-haveStrong backend engineering experience with Python (Django and/or FastAPI)Experience building and operating high-load backend systemsExperience with asynchronous systemsGood understanding of API design for backend ↔ client communicationSolid experience with relational databases (PostgreSQL preferred)Strong execution and ownership mindsetFluent EnglishNice to haveExperience working with cloud infrastructure (AWS or equivalent)Experience working on AI- or ML-enabled productsExperience with other languages (e.g. Go, Ruby)Interest in health, fitness, or consumer-facing productsFluent EnglishWhy working at Zing is awesomeBe part of the fastest-growing fitness and lifestyle startupAI and LLMs are core to the product and part of how we build software day to dayBackend systems with real scale, real users, and real constraintsAI-driven product where backend reliability and performance matterSmall team, high trust, and room to grow through responsibilityCome be a part of something extraordinary at Zing AI Coach – where innovation meets inspiration, and every day brings new opportunities for growth and impact.If you are passionate about understanding user needs and contributing to the development of a user-centered product, we would love to hear from you. Join us and help us create an exceptional user experience for Zing Coach!Apply: https://palta.teamtailor.com/jobs/7174000-senior-backend-developer