Frontend Engineer, Web

About Act

There are over 5 billion users using basic applications today such email, notes, tasks, calendar and they're not AI-native. Our mission is to build proactive applications for anyone in the world, who are not used to complex prompting. We aim to bring intelligence to conversations, errands, organising and workflows, with minimal to no prompting.

Our first application is an agent-first mobile communication app. We believe building applications that users use daily for communication, coordination and collaboration needs will help integrate AI into their lives. The net effect is to eliminate misinformation, achieve low coordination costs, enable high quality tasks and collaboration at scale with minimal or little prompting.

Role

• Build and maintain web applications across Chat, Notes, Calendar, Docs and Sheets using React and TypeScript

• Develop interactive features including real-time messaging, rich-text editing, scheduling, tables and spreadsheets

• Build reusable frontend components and architecture across multiple applications

• Integrate backend APIs, WebSockets and streaming AI responses into product workflows

• Manage complex application state, real-time updates and data synchronisation

• Optimise frontend performance, responsiveness and compatibility across browsers and devices

• Work with product, design and backend engineers to develop, test and release new features

Requirements

• 3+ years of frontend engineering experience building production web applications

• Strong proficiency in React, TypeScript, JavaScript, HTML and CSS

• Experience with frontend architecture, state management and reusable component design

• Experience building interactive interfaces with complex user flows and application state

• Experience integrating REST or GraphQL APIs, WebSockets and asynchronous data

• Understanding of browser performance, rendering, accessibility and responsive design

• Strong debugging skills and ability to maintain frontend reliability in production

Nice to Have

• Experience building chat, collaboration, productivity or document editing applications

• Experience with rich-text editors, collaborative editing or spreadsheet interfaces

• Experience with Next.js and modern frontend build tools

• Experience integrating LLM APIs, streaming AI responses or AI-powered product features