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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Full Stack Engineer - **Company:** Socium - Teams Done Differently - **Location:** Madrid, Spain - **Contract:** Permanent contract - **Skills:** Java (Programming Language), Application Programming Interfaces (APIs), Amazon Web Services, Cloud Computing, Code Review, Databases, Relational Databases, DevOps, Document-Oriented Databases, Virtual Private Networks (VPN), PostgreSQL, Apache Maven, MongoDB, Networking Basics, OpenID, Scrum Methodology, Data Streaming, Systems Integration, Web Applications, Okta, Apache Yarn, ReactJS, Backend, Front End Software Development - **Published:** August 23, 2026 - **Apply:** https://www.buscojobs.com.es/full-stack-engineer-en-alcobendas-ID-368626809 ## About the Role 4-7 years of professional experience as a fullstack developer Hands-on backend experience with Java 17 and Maven Hands-on frontend experience with React and Yarn Practical experience with both a relational database (PostgreSQL) and a document database (MongoDB) Comfortable working across the stack and owning a feature from API to UI Good communication skills and comfort working with distributed, cross-functional teams A pragmatic, quality-conscious approach to code, testing, and documentation Nice to Have Experience with AWS (ECS, Secrets Manager, VPN/networking basics) Familiarity with SSO/OIDC and Keycloak Exposure to B2B SaaS platforms, client portals, or back-office integration domains Our Tech Stack Java 17 · Maven · React · Yarn · PostgreSQL · MongoDB · AWS · Keycloak ## Description Fullstack Developer - Client Portal PlatformMid-Senior Level | Engineering - Integrations & ProductAbout the RoleOur client portal platform is a cloud-based web application that gives customers of professional services firms a browser-based and mobile experience to view their account information, access documents, and communicate with their service provider.Its built to be scalable, modular, brandable, and easy to integrate into each clients existing infrastructure.Were looking for a mid-to-senior fullstack developer to help build and evolve this platform end to end - from the Java/Spring backend services to the React-based frontend - while working closely with the teams responsible for third-party integrations, platform infrastructure, and the wider product.What Youll DoDesign, build, and maintain features across the platforms stack, spanning multiple regional environmentsDevelop backend services in Java 17 with Maven, and frontend components in React with YarnWork with PostgreSQL and MongoDB (Atlas Database) to model, query, and optimise account and document dataIntegrate with regional identity providers (Keycloak) for authentication, and with internal data and document-archive services for account and document dataContribute to the work needed for integration with a third-party back-office platform, including required user-management functionality, and support both pull and push data flowsWrite clean, tested, well-documented code, and take part actively in code reviewsCollaborate with Product, QA, and DevOps within an agile setup - sprint planning, refinement, and retrosHelp troubleshoot issues across the stack, including occasional 2nd-line support and root-cause analysisContribute to CI/CD pipelines and deployments on AWSHelp keep the portal scalable, modular, and brandable as new clients and integrations come on boardWhat Were Looking For4-7 years of professional experience as a fullstack developerHands-on backend experience with Java 17 and MavenHands-on frontend experience with React and YarnPractical experience with both a relational database (PostgreSQL) and a document database (MongoDB)Comfortable working across the stack and owning a feature from API to UIGood communication skills and comfort working with distributed, cross-functional teamsA pragmatic, quality-conscious approach to code, testing, and documentationNice to HaveExperience with AWS (ECS, Secrets Manager, VPN/networking basics)Familiarity with SSO/OIDC and KeycloakExposure to B2B SaaS platforms, client portals, or back-office integration domainsOur Tech StackJava 17 · Maven · React · Yarn · PostgreSQL · MongoDB · AWS · Keycloak ## Related Videos - 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