Job Summary: We are seeking a Junior Full Stack Developer to work on the development of internal products focused on AI, APIs, modern front end, and crawlers. Key Highlights: 1. Work in applied AI and websites/portals 2. Development with Java, React/Next.js, and SQL 3. Brazil’s energy transition journey With over 20 years of experience, we are part of Vibra—the largest multi-energy platform in Brazil—and a reference in the energy market. Our operations span Energy Efficiency, Free Energy Market, Decarbonization, Electric Power, and Renewable Generation, including more than 100 solar power plants. Shall we build a more sustainable future for future generations—together? Transformational energy lies in the diversity of our talents, and we believe it is essential to foster an increasingly diverse and inclusive workplace. Therefore, we actively encourage applications from people with disabilities, Black individuals, women, LGBTQIAP+, people aged 60+, and Indigenous peoples. Join our team and be part of Brazil’s energy transition journey! **Responsibilities and Duties** We are looking for a **Junior Full Stack Developer** responsible for: * Developing and enhancing internal products focused on applied AI and websites/portals, working on interfaces, user journeys, and automations. * Building and maintaining Java-based APIs and services, ensuring organization, logging, error handling, and maintainability. * Developing modern front end (e.g., React/Next.js), including page creation, components, forms, tables, filters, and API consumption. * Working with SQL for queries, data investigation, and validation used in products. * Creating and operating crawlers and data collectors, following best practices such as respecting robots.txt, rate limiting, retries, data normalization, persistence, logging, and traceability. * Integrating generative AI into products (API calls, prompt engineering, response formatting, and applying basic guardrails). * Supporting retrieval-augmented generation (RAG) initiatives—connecting knowledge bases, improving relevance, and evaluating response quality. * Participating in the engineering workflow, including Git version control, pull requests, code reviews, basic testing, and concise documentation. **Requirements and Qualifications** **Requirements:** * Completed undergraduate degree in Computer Science, Engineering, Information Systems, Systems Analysis and Development, Data Science, or related fields. * Prior experience developing backend applications in Java (Spring Boot preferred) and building/consuming REST APIs. * Knowledge of SQL, including JOINs, aggregations, filtering, and data validation. * Experience with modern frontend development using React, Vue, or Angular (React + Next.js preferred). * Hands-on experience with Git/GitHub for version control—including branching, commits, and pull requests. * Familiarity with crawler development and data collection, adhering to web scraping best practices. * Experience or practical exposure to Generative AI—including API integration and basic prompt usage. **Desirable Skills:** * Experience with Spring Boot for Java backend development. * Knowledge of Next.js for frontend development. * Basic understanding of Docker for creating and running containerized environments. * Entry-level experience with unit testing. * Familiarity with CI/CD and pipeline automation. * Awareness of application security best practices (basic OWASP principles). * Understanding of prompt engineering and AI model response formatting. * Knowledge of RAG (retrieval + generation), embeddings, and response quality evaluation. * Portfolio or GitHub repository featuring complete projects (frontend + backend + database) or well-documented crawlers. **Additional Information** **Work Location:** * São Paulo/SP **Work Model:** * Hybrid – 2 days per week onsite **Shall we transform energy to renew the world? Join Comerc!** With over 20 years of experience, we have become part of Vibra—the largest multi-energy platform in Brazil—and a reference in the energy market, operating across Energy Efficiency, Free Energy Market, Decarbonization, Electric Power, and Renewable Generation, with over 100 solar power plants. In 2024, we surpassed R$ 1 billion in EBITDA, reinforcing our commitment to sustainable growth and national energy transition. Our innovative energy solutions make corporate decarbonization more tangible, precise, and achievable. Here, ESG is not a standalone agenda separate from business strategy—it is how we pursue sustainable development and contribute to a low-carbon economy. Join our team and help shape the future with your energy—working in a collaborative environment full of meaningful challenges and growth opportunities!