Be part of Stefanini! At Stefanini we are more than 30,000 geniuses, connected from 41 countries, doing what they are passionate about and co-creating a better future. **Responsibilities and attributions** * Develops new user-oriented features. * Creates front-end code, components and reusable libraries for future use. * Ensures the technical feasibility of UI/UX designs. * Optimizes the application to achieve optimal response times, optimal stability, security and scalability. * Provides support throughout the entire application lifecycle (Development, testing, release and support). * Performs unit and UI tests to improve development quality. * Conducts root cause analysis for rapid response to incidents in the application being developed. * Ensures that new and legacy applications meet quality standards by performing peer code reviews. * Documents implementations in a simple manner (agile model). * Collaborates with other team members and stakeholders. **Requirements and qualifications** * Advanced knowledge of JavaScript and mastery of HTML5 and CSS. * Advanced experience with CSS preprocessors (Sass, Less) and patterns/nomenclatures such as 7.1 and BEM. * Considers performance during development. * Mastery of advanced JavaScript features (one-page lifecycle, anonymous functions, scoping, polyfilling). * Knowledge of browser differences, their dev tools, and their impact on visual and functional compatibility. * Competence in Server Side Rendering and principles/best practices of SEO. * Mastery of a framework/library, especially **React.js**, and understanding of the V8 engine. * Handling of web security techniques (XSS, injections). * Management of application states (Redux, useContext). * Integration with APIs (Amplify, Axios). * Knowledge of development patterns (Singleton, Observer, Module) and architectural patterns (MVC, Flux). * Handling of asynchronous requests (Async/Await, Promises). * Use of Git: branches, merging to master, pull/merge requests, cherry-pick, rebase and stash. * Configuration of package.json to optimize dependencies and sources. * Application of unit testing (Jest, Testing Library). * Translates complex systems (grids, navigation, pagination, icons) into responsive components. * Knowledge of design tools, especially **Figma**. * Creates reusable components between web and mobile; generates complex prototypes with variations and animations. * Applies UX techniques: tagging, analytics and A/B testing. * Ability to evaluate and question designs. * Experience with Headless CMS (desirable). * Competence in Agile frameworks and mindset. * Knowledge of design patterns, microfrontend architecture, and support/development of Design Systems. **Additional information** Are you looking for a place where your ideas can shine? With over 38 years and a global presence, at Stefanini we transform tomorrow together. Here, every action counts and every idea can make a difference. Join a team that values innovation, respect and commitment. If you are a disruptive person, committed to continuous learning, and innovation is in your DNA, then we are what you are looking for. Come and let's build a better future together!