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 Qualifications~3-5+ years of experienceas a Full Stack or Front-End Engineer~ Strong hands-on experience withReact.
Js and Next.
Js~ Experience building and consumingREST APIs~ Good understanding of backend technologies (Node.
Js required; Python/FastAPI is a plus)~ Experience withcomponent libraries, design systems, or shared UI components~ Familiarity with modern testing frameworks (Jest, Testing Library)~ Good understanding of performance, security, and scalability principles~ Comfortable working in cross-functional agile teams~ Strong 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 Offer
~ Full-time freelance mission~3-month contract, renewable depending on performance and roadmap~ Hybrid environment from BarcelonaSeniority levelMid-Senior levelEmployment typeFull-timeJob functionInformation TechnologyIndustriesPharmaceutical ManufacturingBarcelona, Catalonia, Spain