Client Full-Stack Engineer — IM Chat Platform, Android Focus

Responsibilities

• Design, develop, and maintain client-side applications for an instant messaging platform, with Android as the primary focus
• Build core messaging features: real-time chat, group chat, media messaging, message sync, offline messaging, push notifications
• Participate in client-side architecture design, ensuring consistent UX across Android, iOS, and Web
• Use AI-powered tools (Cursor, GitHub Copilot, ChatGPT, Claude, etc.) to support cross-stack frontend development - read, debug, and modify iOS/Web codebases
• Integrate RESTful APIs and WebSocket/MQTT/gRPC real-time communication protocols
• Handle local storage, offline-first experience, message state management, and cross-platform sync logic
• Optimize client performance: startup speed, memory, battery, network efficiency, UI responsiveness
• Collaborate with backend teams on API design, integration, and production issue investigation
• Senior level: mentor junior engineers, contribute to technical design decisions

Requirements

• Bachelor's degree in Computer Science, Software Engineering, or a related discipline
• Engineer: 1-3+ years of experience; Senior Engineer: 3-5+ years
• Solid production experience in Android development (Kotlin and/or Java)
• Good understanding of Android SDK, Jetpack components, asynchronous programming, and modern client-side architecture
• Required: ability to use AI-powered development tools (Cursor, GitHub Copilot, ChatGPT, Claude, or similar) for cross-stack frontend development
• Able to read, understand, debug, and make reasonable changes in iOS or Web codebases with AI tool support
• Familiarity with WebSocket, MQTT, gRPC, or similar real-time communication protocols
• Understanding of messaging concepts: message delivery, read status, sync, local persistence, offline support, push notifications
• Good understanding of client-side performance optimization, memory management, multithreading, and security best practices
• Familiar with Git, CI/CD pipelines, automated testing, and Agile processes
• Strong debugging, problem-solving, ownership, and communication skills

Preferred Qualifications

• Experience building IM products or communication platforms (WhatsApp, Telegram, WeChat, Discord, Slack, Messenger, etc.)
• iOS development experience (Swift, SwiftUI, Objective-C)
• Web frontend experience (TypeScript, React, Vue, Next.js)
• Cross-platform client or mobile full-stack development experience
• End-to-end encryption, message security, or cryptographic protocols experience
• Voice/video calling or RTC technologies experience
• Large-scale distributed messaging infrastructure experience
• Fintech, payments, or Web3 applications experience
• Open-source contributions or published apps on Google Play/App Store