Freelance Senior OR Junior Full Stack Developer – React / Next.Js / Node.Js – BarcelonaYou will collaborate closely with the Tech Lead, Product Owner, UX Designer, and Data team to design, develop, and deliver high-quality features within an agile environment.ResponsibilitiesDevelop and maintain complex, data-heavy user interfaces usingReact and Next.JsBuild and optimisereusable componentsand contribute to the internal UI libraryDesign and integrateREST APIsand WebSocket endpointsEnsure code quality throughclean architecture and best practicesWriteunit and integration tests(Jest / Testing Library)Collaborate with Product, UX, and Data to deliver features end-to-endParticipate in architecture discussions and decision-makingTroubleshoot and resolve issues across the stackContribute to CI/CD processes and development workflow improvementsMaintain documentation on ConfluenceRequired Qualifications3-5+ years of experienceas a Full Stack or Front-End EngineerStrong hands-on experience withReact.Js and Next.JsExperience building and consumingREST APIsGood understanding of backend technologies (Node.Js required; Python/FastAPI is a plus)Experience withcomponent libraries, design systems, or shared UI componentsFamiliarity with modern testing frameworks (Jest, Testing Library)Good understanding of performance, security, and scalability principlesComfortable working in cross-functional agile teamsStrong communication skills in EnglishNice to HaveExperience with container technologies (Docker, AWS ECR/EKS, OpenShift)Experience with CI/CD pipelinesKnowledge of SonarQube, Checkmarx, or similar code quality toolsExperience in healthcare, pharma, or other regulated environmentsWhat We OfferFull-time freelance mission3-month contract, renewable depending on performance and roadmapHybrid environment from BarcelonaSeniority levelMid-Senior levelEmployment typeFull-timeJob functionInformation TechnologyIndustriesPharmaceutical ManufacturingBarcelona, Catalonia, Spain#J-18808-Ljbffr

📌 Freelance Senior Or Junior Full Stack Developer - React / Next.Js / Node.Js - Barcelona (Madrid)
🏢 Blu Selection Recruitment Agency
📍 Madrid