Location: São Paulo, Brazil Work Mode: Remote At Sii Group Colombia, we’re looking for a Full Stack Developer (React/Java) to join a high-impact international project. This opportunity is ideal for someone with strong front-end expertise in React, solid backend skills in Java, and the ability to guide technical decisions while contributing to high-quality software delivery. Requirements: 5+ years of experience in React and front-end development Solid knowledge of Java backend development Upper-intermediate to advanced English level (B2–C1) Strong expertise in modern front-end practices and UI frameworks Experience with Spring Boot, microservices, and architectural patterns Familiarity with message brokers and cloud technologies Knowledge of Event-Driven Architecture Strong communication, negotiation, and consultancy skills Experience leading technical teams (up to 6 people) Responsibilities: Develop and maintain front-end applications with React (approx. 70%) Contribute to backend development with Java and Spring Boot (approx. 30%) Ensure code quality through CI/CD pipeline checks, unit and integration tests Collaborate in design decisions and participate in peer code reviews Guarantee alignment of front-end and backend components with contract specifications Guide and support small teams in technical implementation and architecture