Senior Front end Engineer [Brazil]

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 and with +50M users having conversations on Arena per month and engaging with our Agent AI.

Sometimes you're stuck in a job that doesn't make sense. Refactoring code from ages ago, the stack is miles away from what it's supposed to be. If you love a good challenge, you're a curious developer who experiments with AI and AI agents every day, and you want to be a part of one of the fastest-growing AI startups in Silicon Valley — then Arena is the company you're looking for.

What you will be doing:

As a senior front end engineer, you will have an enormous impact on making our app and API service faster, more scalable and more flexible. Our team is made up of very experienced engineers, some with more than 10 years of experience. You will collaborate with product and engineering teams to ship AI-powered features and make the existing ones perform orders of magnitude faster.

The challenges:

Real-time messaging to support 500,000 concurrent users per customer application;

• Design and build AI applications, including Agents and model fine-tuning.

• Building for Performance - Delivering ultra-fast web applications optimized for performance.
• Complex Debugging - Investigating tricky issues and crafting robust solutions.

• High availability: our code is running on homepages of the most visited websites and apps in the internet

Our Stack:

• React.js & Next.js - The foundation of our modern frontend applications.
• TypeScript - Ensuring type safety and maintainable code.
• Web Components - Creating reusable and framework-agnostic UI elements.
• Advanced CSS - Leveraging CSS-in-JS, animations, and layout mastery.
• Figma - Collaborating closely with designers to bring UI/UX visions to life.

 Work Experience:

• 6+ years of relevant Frontend programming experience

Must-Have Experience:

• TypeScript
• React
• Next.js
• GraphQL
• Git
• WebSocket

Nice-to-Have Experience:

• Styled Components
• Gitflow
• Github Actions
• Gatsby
• Webpack
• Monorepo
• Google Firebase/Firestore
• Node.js

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 similar to Reddit, Discord, and Whatsapp.
• 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

⛱️ 5 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

About Arena:

Arena is 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, growth, and responsibility).