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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Full Stack Engineer - **Company:** Socium - Teams Done Differently - **Location:** Coslada, Spain - **Contract:** Permanent contract - **Skills:** Java (Programming Language), Application Programming Interfaces (APIs), Amazon Web Services, 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 26, 2026 - **Apply:** https://www.buscojobs.com.es/full-stack-engineer-en-coslada-ID-368898197 ## About the Role keep the portal scalable, modular, and brandable as new clients and integrations come on board What We're Looking For 4-7 years of professional experience as a fullstack developer Hands-on backend experience with Java 17 and Maven Hands-on frontend experience with xiphteb 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 Platform Desplácese hacia abajo para encontrar una descripción detallada de este trabajo y lo que se espera de los candidatos.Envíe su solicitud haciendo clic en el botón "Solicitar".Mid-Senior Level | Engineering - Integrations & Product About the Role Our 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.It's built to be scalable, modular, brandable, and easy to integrate into each client's existing infrastructure.We're 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 You'll Do Design, build, and maintain features across the platform's stack, spanning multiple regional environments Develop backend services in Java 17 with Maven, and frontend components in React with Yarn Work with PostgreSQL and MongoDB (Atlas Database) to model, query, and optimise account and document data Integrate with regional identity providers (Keycloak) for authentication, and with internal data and document-archive services for account and document data Contribute 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 flows Write clean, tested, well-documented code, and take part actively in code reviews Collaborate with Product, QA, and DevOps within an agile setup - sprint planning, refinement, and retros Help troubleshoot issues across the stack, including occasional 2nd-line support and root-cause analysis Contribute to CI/CD pipelines and deployments on AWS Help keep the portal scalable, modular, and brandable as new clients and integrations come on board What We're Looking For 4-7 years of professional experience as a fullstack developer Hands-on backend experience with Java 17 and Maven Hands-on frontend experience with xiphteb 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 ## Related Videos - [Build and Deploy a Fullstack App with Open Source Tooling](https://www.wearedevelopers.com/videos/775-build-and-deploy-a-fullstack-app-with-open-source-tooling) - [From DevOps to Scaled DevOps: How We’re Rebuilding Continuous Delivery as a Platform](https://www.wearedevelopers.com/videos/100018-from-devops-to-scaled-devops-how-we-re-rebuilding-continuous-delivery-as-a-platform) - [Keeping applications secure by evolving OAuth 2.0 and OpenID Connect](https://www.wearedevelopers.com/videos/100152-keeping-applications-secure-by-evolving-oauth-2-0-and-openid-connect) - [Empowering Thousands of Developers: Our Journey to an Internal Developer Platform](https://www.wearedevelopers.com/videos/1519-empowering-thousands-of-developers-our-journey-to-an-internal-developer-platform) - [DevOps Maturity Check – a way to balance autonomy and alignment](https://www.wearedevelopers.com/videos/58-devops-maturity-check-a-way-to-balance-autonomy-and-alignment) - [Delegating the chores of authenticating users to Keycloak](https://www.wearedevelopers.com/videos/1558-delegating-the-chores-of-authenticating-users-to-keycloak) ## Related Articles - 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