Senior Fullstack Developer (React / Java / Node)

This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Fullstack Developer (React / Java / Node) based in Brazil. This role offers the opportunity to build and evolve enterprise-scale digital solutions within a highly collaborative and technology-driven environment. You will contribute to the design, development, and support of secure, scalable web applications with real business impact. The position combines frontend and backend expertise, working across modern frameworks, cloud-ready architectures, and complex integrations. You will collaborate with multidisciplinary teams, including product, UX, architecture, and quality specialists, in an Agile setting. The ideal candidate enjoys solving complex technical challenges and improving systems through innovation and engineering excellence. This is a senior-level opportunity for developers who want to influence architecture decisions and deliver high-quality software solutions. Accountabilities: The Senior Fullstack Developer will be responsible for designing, implementing, and maintaining robust applications while collaborating with cross-functional teams to deliver reliable and scalable technology solutions. Design, develop, test, and integrate full-stack application components using modern frontend and backend technologies. Build scalable web applications using React for frontend development and Java with Spring Boot for backend services. Develop RESTful APIs, microservices, and integrations with enterprise platforms and internal systems. Collaborate with UX/UI, product, architecture, and QA teams to deliver high-quality solutions within an Agile environment. Create and maintain technical documentation, including architecture designs and system specifications. Ensure application quality, performance, reliability, and security by applying best practices around authentication, authorization, and secure coding. Work with databases and backend technologies, including MySQL, Hibernate, Spring Data, and Spring Security. Monitor and troubleshoot production applications using observability tools, supporting incident resolution and participating in on-call rotations when required. Contribute to continuous improvement initiatives focused on scalability, maintainability, and engineering excellence. Requirements: The ideal candidate has strong full-stack development experience, excellent problem-solving abilities, and the ability to communicate effectively while working on complex enterprise applications. Solid professional experience in full-stack software development. Strong hands-on expertise with React, modern JavaScript (ES6+), DOM APIs, and JSON. Advanced backend development experience with Java, including recent hands-on experience with Spring Boot. Experience designing and implementing microservices and enterprise integration patterns. Strong knowledge of relational databases, SQL, and database-driven application development. Understanding of web security concepts, including OAuth2, OIDC, JWT, authentication, and authorization practices. Experience with application monitoring, debugging, error handling, and production support processes. Strong analytical and problem-solving skills with a structured approach to technical challenges. Clear communication skills and the ability to collaborate effectively with technical and business stakeholders. Availability to work within the EST time zone. Nice-to-have experience with micro-frontend architecture, component libraries such as Storybook or styled-components, event-driven architecture, and Kafka. Benefits: The role offers a comprehensive benefits package designed to support professional growth, health, well-being, and work-life balance. Health and dental insurance. Meal and food allowance. Childcare assistance. Extended paternity leave. Access to gym, fitness, and wellness partnerships. Profit sharing and results participation programs. Life insurance coverage. Continuous learning opportunities through internal education platforms. Discounts through partner programs. Access to online platforms focused on physical, mental, and overall well-being. Pregnancy and responsible parenting support programs. Partnerships with online learning platforms. Language learning resources. Remote work environment and flexible collaboration model. How Cobalt Streamworks works: We use an AI-powered matching process to ensure your application is reviewed quickly, objectively, and fairly against the role's core requirements. Our system identifies the top-fitting candidates, and this shortlist is then shared directly with the hiring company. The final decision and next steps (interviews, assessments) are managed by their internal team. We appreciate your interest and wish you the best! Why Apply Through Cobalt Streamworks? Data Privacy Notice: By submitting your application, you acknowledge that Cobalt Streamworks will process your personal data to evaluate your candidacy and share relevant information with the hiring employer. This processing is based on legitimate interest and pre-contractual measures under applicable data protection laws (including GDPR). You may exercise your rights (access, rectification, erasure, objection) at any time. #LI-CL1