Frontend React Developer

KSTACK; São Paulo; On-site; BRL 120,000 - 180,000; Full time

Job summary

KSTACK is seeking a creative Frontend React Developer to build dynamic, high-performance web applications. You will collaborate with UI/UX designers, back-end engineers, and global teams to deliver scalable interfaces using React.js and modern JS.

Experience with AI-powered productivity tools, REST/GraphQL, and responsive design is valued. You will write maintainable code, participate in reviews, and help advance front-end standards.

Qualifications

• 3+ years of professional front-end development experience with React.js.
• Strong proficiency in JavaScript (ES6+), TypeScript, HTML5, and CSS3/SCSS.
• Solid understanding of state management with Redux Toolkit, Context API, Zustand, or Recoil.
• Experience with API integration using Axios or Fetch and modern build tools (Webpack, Vite, Babel, npm/pnpm/yarn).
• Knowledge of responsive design frameworks and UI libraries (Tailwind, MUI, Styled Components, Bootstrap).
• Experience with Git-based version control and platforms like GitHub, Azure DevOps, or GitLab.

Responsibilities

• Design, develop, and maintain React.js components for enterprise web apps.
• Collaborate with UI/UX to translate wireframes into polished interfaces.
• Optimize front-end performance for speed, responsiveness, and cross-browser compatibility.
• Integrate front-end with RESTful APIs, GraphQL, and back-end services.
• Participate in code reviews, sprint planning, and daily stand-ups in an Agile environment.
• Troubleshoot front-end defects and performance bottlenecks across modern browsers.
• Create and maintain documentation, component libraries, and front-end standards.
• Stay current with new front-end tech and software engineering best practices.
• Leverage AI-powered tools to accelerate development, refactoring, testing, and docs.

Skills

React.js

JavaScript (ES6+)

TypeScript

HTML5/CSS3

Redux Toolkit/Context API

Axios/Fetch

Git

Webpack/Vite

Tools

GitHub

Azure DevOps

GitLab

Job description

Role Summary

We are looking for a creative, detail-oriented Frontend React Developer with hands-on experience building dynamic, high-performance web applications. The ideal candidate has a strong foundation in front-end architecture, writes clean and maintainable code, and has a solid understanding of modern JavaScript frameworks and development practices.

In this role, you will leverage modern AI-powered productivity tools and work closely with UI/UX designers, back-end engineers, and global cross-functional teams to build scalable user interfaces and deliver exceptional user experiences.

Key Responsibilities

• Design, develop, and maintain efficient, reusable, and reliable React.js components for enterprise web applications.
• Partner with UI/UX designers to translate wireframes, mockups, and user stories into polished, high-quality user interfaces.
• Optimize front-end applications for speed, performance, responsiveness, and cross-browser compatibility.
• Integrate front-end applications with RESTful APIs, GraphQL endpoints, and back-end services.
• Actively participate in code reviews, sprint planning, and daily stand-ups within an Agile development environment.
• Troubleshoot and resolve front-end defects, memory leaks, and performance bottlenecks across modern browsers.
• Create and maintain technical documentation, component libraries, and front-end development standards.
• Stay current with emerging front-end technologies, web standards, and engineering best practices to drive continuous improvement.
• Leverage AI-powered development tools to accelerate feature development, code refactoring, unit testing, and technical documentation.

Technical & Mandatory Skills

React & Front-End Core Stack

• 3+ years of professional front-end development experience building modern web applications with React.js.
• Strong proficiency in JavaScript (ES6+), TypeScript, HTML5, and CSS3/SCSS.
• Solid understanding of state management tools and patterns, including Redux Toolkit, Context API, Zustand, or Recoil.
• Hands-on experience with asynchronous request handling, API integration, and JSON data using Axios or the Fetch API.
• Familiarity with modern front-end build pipelines and development tools, including Webpack, Vite, Babel, and npm/pnpm/yarn.
• Strong understanding of responsive design frameworks and styling libraries such as Tailwind CSS, Material UI, Styled Components, or Bootstrap.
• Experience with Git-based version control and development workflows using platforms such as GitHub, Azure DevOps, or GitLab.

Quality & Engineering Standards

• Good understanding of testing frameworks and tools such as Jest, React Testing Library, or Cypress.
• Understanding of browser rendering behavior, DOM manipulation, and front-end performance optimization techniques.

AI Tools Experience

Hands-on experience using modern AI-powered tools to improve developer productivity, including:

• GitHub Copilot or Cursor for AI-assisted code generation and refactoring.
• ChatGPT, Claude, or enterprise Generative AI assistants for rapid debugging, algorithm design, and technical documentation.
• AI-powered tools for code analysis, testing, or code completion.

Preferred Qualifications

• Exposure to modern React frameworks such as Next.js, as well as Server-Side Rendering (SSR) and Static Site Generation (SSG) concepts.
• Familiarity with CI/CD pipelines for front-end application deployments.
• Basic understanding of Web Content Accessibility Guidelines (WCAG) and SEO best practices.
• Familiarity with Agile project management tools such as Azure DevOps or Jira.

Soft Skills

• Communication: Strong written and verbal English communication skills, with the ability to collaborate effectively with global development teams.
• Analytical Thinking: Strong problem-solving skills with excellent attention to detail and UI precision.
• Ownership & Accountability: Ability to take ownership of features from technical task breakdown through production release.
• Adaptability: Eagerness and ability to quickly learn new libraries, frameworks, and engineering tools.