Fullstack Developer – Client Portal Platform
Mid–Senior Level | Engineering – Integrations & Product
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.
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
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)
~ A pragmatic, quality-conscious approach to code, testing, and documentation

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
Java 17 · Maven · React · Yarn · PostgreSQL · MongoDB · AWS · Keycloak

📌 Full Stack Engineer (hybrid or remote) (Madrid)
🏢 Socium - Teams Done Differently
📍 Madrid