Lead Full Stack Developer

About the JobNexaQuanta offers expert consulting and implementation services for Generative AI-powered transformation of businesses and software applications in a responsible, safe, and cost-effective manner to drive higher revenues, profitability, and productivity. Headquartered in London, UK, NexaQuanta is a team of highly experienced Generative AI Consultants, Architects, Researchers, Data Scientists, and Software Developers, delivering advanced Generative AI-powered transformation solutions to numerous large enterprises globally. We are an IBM Silver Business Partner, bringing our customers the best and most trusted IBM watsonx Generative AI technologies and solutions.We are looking for a Lead Full Stack Developer with 8+ years of hands-on experience to design and build scalable, secure, and high-performance applications across our frontend and backend stack — from React/Next.js interfaces to Node.js services, Kafka-based event streaming, and Keycloak-based identity and SSO.ResponsibilitiesBuild responsive, high-performance user interfaces using React.js, Next.js, and PrimeReact.Design and develop scalable Node.js applications with PostgreSQL integration.Implement and iterate on UI/UX improvements to enhance user experience and drive engagement.Build new features and enhance existing functionality on our custom applications.Deploy and manage applications on AWS infrastructure using Docker containers.Implement integrations with marketing platforms, analytics tools, and other external services.Implement and maintain Keycloak-based single sign-on, identity federation, and fine-grained access control across our application suite.Design and build Kafka producers and consumers for real-time data flows, asynchronous processing, and service-to-service integration.Ensure applications are optimized for speed, scalability, and user experience.Write clean, maintainable code with proper testing and documentation.Requirements8+ years of hands-on experience in full-stack development.Advanced proficiency in React.js and strong expertise in Next.js (SSR/SSG); experience with PrimeReact or similar component libraries.Strong experience with Node.js (Express.js/Fastify), RESTful APIs, and GraphQL.Practical experience designing and operating Apache Kafka event streaming pipelines (producers, consumers, topics, partitions, consumer groups) in production.Hands-on experience implementing SSO using OAuth 2.0 / OIDC with Keycloak (or equivalent such as Auth0, Okta, or Entra ID), including JWT lifecycle management and RBAC/multi-tenant authorization.Strong PostgreSQL and advanced SQL skills; experience with MongoDB or similar NoSQL databases and ORM/query builders (Prisma, Sequelize).Demonstrable AWS (EC2, S3, Lambda, RDS, CloudFront) and Docker experience; CI/CD pipelines and Infrastructure as Code preferred.Solid understanding of event-driven microservices architecture, modular monoliths, and asynchronous processing patterns (retries, dead-letter queues).Strong grasp of security best practices (OWASP) and secure API design/authentication standards.Proficiency with Git/GitHub and Agile/Scrum methodologies.Excellent problem-solving, communication, and collaboration skills.What We OfferCompetitive salary and comprehensive benefits package.Opportunity to work on cutting-edge AI-powered projects with a world-class team.Professional growth and continuous learning opportunities.Flexible working arrangements and a modern development environment.Access to the latest technologies and tools.Career advancement opportunities in a rapidly growing company.Collaboration with international teams and exposure to global projects.