Front end Engineer [Brazil]

About Arena: Arena is a startup created in Silicon Valley with a mission to build communities for creators, publishers and brands with the power of AI. Companies using Arena include Disney, Reuters, Fox, Red Bull and NFL. We have +2,000 customers in 150 countries, with +50M users engaging and having conversations on Arena every month. We are a Series A company backed by top-tier investors such as CRV, Redpoint and Craft Ventures. Arena offers a unique work environment and the chance to collaborate with diverse teammates across multiple countries, with a culture of ownership, autonomy, and high performance. Arena is expanding its AI product portfolio with MyAvatar.AI, a multimodal platform that enables users to create intelligent, personalized AI avatars through voice, video, and conversational interfaces. Sometimes you're stuck in a job that doesn't make sense, working with outdated code and a stack that holds you back. If you love a good challenge, enjoy solving meaningful problems, and want to be part of a fast-growing AI startup in Silicon Valley — then Arena is the company you're looking for. About the Role: We’re looking for a Frontend Engineer to build fast, scalable, and high-performance web experiences across Arena’s products. You’ll work closely with Product, Design, and Engineering to build AI-powered features, improve existing applications, and solve complex frontend and performance challenges. You’ll work alongside experienced engineers and have a direct impact on products used by millions of users. What you will be doing: - Build and maintain high-performance frontend applications using React, Next.js, and TypeScript. - Develop real-time experiences and interfaces using WebSockets and GraphQL. - Build reusable, scalable, and maintainable UI components and frontend architecture. - Integrate frontend applications with APIs, AI services, and backend systems. - Optimize application performance, scalability, and reliability across high-traffic environments. - Collaborate with Product and Design to turn product requirements and UI/UX concepts into polished experiences. - Debug complex frontend and production issues and implement robust solutions. - Contribute to AI-powered features, including conversational experiences and AI Agents. Must-Have Experience: - 3+ years of professional frontend engineering experience. - Strong experience with TypeScript and React. - Production experience with Next.js. - Experience working with GraphQL and REST APIs. - Experience building real-time applications using WebSockets. - Experience with Git and collaborative software development workflows - Experience working in monorepo environments. - Strong problem-solving skills and attention to performance, scalability, and code quality. - Fluent English Our Stack: - Frontend: React.js, Next.js, TypeScript. - UI: Web Components, CSS, Styled Components. - APIs & Real-Time: GraphQL, REST, WebSockets. - Build & Architecture: Monorepo, Turborepo, Webpack. - Infrastructure & CI/CD: GitHub Actions, Firebase, Firestore. - Design: Figma. Nice-to-Have Experience: - Styled Components or other CSS-in-JS solutions. - Turborepo, Webpack, or similar frontend tooling. - GitHub Actions and CI/CD workflows. - Node.js and backend development. - Firebase and Firestore. - Experience building browser extensions or WordPress plugins. - Experience with AI-powered products, conversational interfaces, or AI Agents. Example Projects You’ll Be Working on: - Implement applications using Next.js framework - Build a real-time chat that can scale to 1M simultaneous users - Develop plugins for WordPress and Google Chrome - Implement high-performance widgets - Build a JavaScript SDK - Build and design AI features and AI agents We also have some sweet perks like: 🔥 Be a part of the team in Silicon Valley and join a global team. 💪 A team of exceptional engineers leading the cutting-edge AI Agents. 💶 Competitive salary package & benefits. ⛱️ 4 weeks of paid time-off. 📖 Learning and Development budget. 🚀 Key moment to join Arena in terms of growth and opportunities. 💻 Ability to put your stamp on real-world AI applications that serve millions of users. 📚 Fast-learning environment, entrepreneurial and strong team spirit. 🌍 Multiple nationalities: cosmopolite & multi-cultural mindset. 💆‍♀️ Our people matter, work-life balance is important at Arena.