At **LeaderMedia**, we help companies scale their technology by developing proprietary projects or providing qualified intellectual capital to strengthen internal teams. We are looking for a person passionate about technology, performance, and user experience to join our team. **What you’ll do (Responsibilities):** * Participate in the full development lifecycle (end\-to\-end), from database modeling to user interface. * Develop scalable and secure APIs (Node.js/Nest.js) integrated with modern, high-performance interfaces (React/Next.js). * **Write and maintain automated tests on both ends (Unit, Integration, and E2E) to ensure delivery robustness.** * Make architectural decisions involving both Back\-End (SOLID, Clean Architecture) and Front\-End (Componentization, State Management). * Optimize application performance (database queries, server-side caching, and Core Web Vitals on the client side). * Work with containerization (Docker) and support DevOps culture. **Required Qualifications (Hard Skills):** * **Language:** Advanced proficiency in JavaScript and TypeScript. * **Front\-End:** Solid experience with React, Next.js, Tailwind CSS, and React Hook Form. * **Back\-End:** Experience with Node.js (Express, Fastify) and structured frameworks such as **Nest.js**. * **Databases:** Database modeling and manipulation of Relational (PostgreSQL/MySQL) and NoSQL databases. * **Code Quality:** Mandatory hands-on experience writing automated tests (Jest, Vitest, Cypress, or Testing Library). * **Architecture:** Knowledge of design patterns, SOLID principles, and Clean Architecture. * **Infrastructure/Tools:** Docker, Git, and caching concepts (Redis). **Nice-to-Have:** * Experience with the **Bun** runtime. * Knowledge of messaging systems (RabbitMQ, Kafka). * Experience with Server Actions and Next.js’s new App Router. * Familiarity with CI/CD pipelines and Cloud platforms (AWS/GCP). **Soft Skills We Value:** * Ownership mindset toward delivered features. * Strong communication skills and ability to work collaboratively. * Problem-solving orientation for complex challenges. * Willingness to learn and share knowledge. Job Type: Freelance / PJ Compensation: R$8\.000,00 \- R$15\.000,00 per month Experience: * Years of experience in frontend and backend (Mandatory) Work Location: Remote