Full Stack Developer (Java + React + Elasticsearch)

**Advanced English (B2\+) Mandatory** **Contract for 12 months with the possibility of extension.** **At least 5\+ years of experience with Java/SpringBoot and React** **Working experience with ElasticSearch or similar technologies (required)** We are looking for a Senior Full Stack Developer with strong expertise in building scalable enterprise applications using Java (Spring Boot) on the backend and React on the frontend. The ideal candidate will have hands\-on experience with microservices architecture, advanced JavaScript/TypeScript, and be comfortable working with distributed systems using SAGA and CQRS patterns. Experience with ElasticSearch and AWS services is required. Responsabilities: * Design, develop, and maintain scalable backend services using Java and Spring Boot * Build and optimize user\-facing components using React.js, JavaScript, and TypeScript * Architect and implement microservices with asynchronous communication (e.g., Kafka) * Apply and support SAGA and CQRS patterns in distributed system design * Integrate and query ElasticSearch to support search and analytics features * Write clean, efficient, and well\-documented code following best practices * Collaborate with cross\-functional teams (Product, DevOps, QA) to deliver high\-quality software * Participate in code reviews, provide constructive feedback, and maintain coding standards * Troubleshoot and debug issues across the stack — from UI to backend services and databases * Use AWS services (like EKS, ECR, S3\) to deploy and manage applications in the cloud * Continuously improve performance, security, and scalability of applications * Stay updated on emerging technologies and propose improvements to architecture and workflows Mandatory Requirements: **Backend (Java):** * 5\+ years of experience with Java (Java 8 or newer), including strong core concepts: * Functional interfaces, transient and volatile keywords, marker interfaces, Integer Caching, HashMap internals (collisions, default size, load factor) * Strong experience with Spring Boot and the Spring ecosystem (Spring Data, Security, etc.) * Familiarity with tools like Spring Actuator and advanced configuration/annotations * Experience developing microservices and working with asynchronous communication (Kafka or similar message brokers) * Understanding of SAGA and CQRS design patterns * Experience integrating or working with ElasticSearch **Frontend (React):** * 4\+ years of experience working with React.js * Proficient in React Hooks: useEffect, useRef, useContext, useMemo, useCallback * State management using Redux and/or React Query * Strong knowledge of JavaScript (ES6\+) and TypeScript * Ability to explain and work with concepts like pure functions, closures, array methods like splice, and type differences (any vs unknown) **Cloud / DevOps:** * Experience working with AWS services, especially: * EKS, ECR, S3 * Comfortable working in CI/CD environments, containers (Docker, Kubernetes)