This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Back-end Developer (Java + Node.js) based in Brazil. We are looking for an experienced back-end developer to design, build, and maintain scalable, high-performance services supporting applications used by millions of people. In this role, you will contribute to the architecture and development of new solutions from the ground up, balancing product delivery with technical excellence. You will work primarily with Java, Spring Boot, and Node.js in a cloud-native environment, leveraging AWS, microservices, and modern engineering practices. Quality, security, observability, and automated testing will be central to your work. You will collaborate closely with Product and Front-end teams, bringing autonomy, problem-solving skills, and a strong focus on business outcomes. This is an opportunity to shape technical solutions in a challenging, collaborative environment that embraces innovation and AI-powered software development.