Senior Mobile Engineer (React Native & Hybrid)

Team Segment : Music

About the Role:

We're building a music streaming app that millions of people in Japan use every day — and there's a ton of new ground to cover. We are gradually expanding our technical stack from pure native (iOS/Android) to cross-platform solutions, with React Native as our primary driver for new features and fast iteration.

Since our existing team is composed of seasoned native specialists, you will help us build our React Native foundation and be a key voice in our technical decisions. You will help design the integration of React Native into our existing apps, and establish our RN technical standards.

You will act as the technical bridge between our cross-platform and native domains, partnering with veteran iOS and Android specialists to navigate complex mobile puzzles—such as low-latency audio sync, background tasks, and hybrid bridge optimizations. It's the perfect environment to push your platform engineering skills to the next level while shaping our core architecture.

Team & Culture: You'll join a Scrum-based cross-functional squad with iOS, Android, backend, QA engineers, product managers, and designers. We move fast, ship often, and value engineers who enjoy collaborating across different technical stacks.

Responsibilities:

• Build and evolve our React Native Architecture: Work with the team to shape the blueprint, folder structures, and standards for our hybrid app
• Ship high-quality, user-facing features across iOS and Android
• Collaborate closely with native iOS and Android developers to integrate and maintain native bridges, exposing core native capabilities (e.g., our custom audio engine) to the React Native layer
• Own mobile features end-to-end: UI, API integration, release, and post-launch optimization
• Improve app quality: Optimize React Native performance (startup time, memory usage, and frame rates)
• Stay adaptable: Participate in evaluating and prototyping other cross-platform or emerging technologies if our product direction evolves

Requirements:

• Strong production experience with React Native and TypeScript, including performance tuning and state management.
• Comfortable with Mobile Development Environments: Navigating native iOS (Xcode) and Android (Android Studio) project structures, managing dependencies (CocoaPods, Gradle), and troubleshooting native build/linking errors.
• Deep understanding of mobile platform fundamentals (UI lifecycles, memory management, and multi-threading).
• Strong experience in shipping production-grade mobile features. Whether you've built a product from scratch or scaled a significant feature in a large codebase, we value your ability to deliver quality and stability.
• Comfortable with App Store / Google Play submission, OTA updates, and release workflows.

Nice to Have:

• Prior experience or a strong interest in learning Swift (iOS) or Kotlin (Android) to help you navigate and understand the existing native codebases.
• Product sensibility — forms opinions about what to build, not just how.
• Experience with AI-assisted development tools (Claude Code, GitHub Copilot).
• Exposure to other cross-platform technologies (e.g., Flutter, Kotlin Multiplatform) to help guide our architectural decisions.

Why Join Us: You get the reach of a product with millions of daily users and the speed of a team that ships constantly. There's no shortage of things to build — you'll see your work in the hands of real people fast, and you'll have the freedom to reach across the stack when that's what makes sense. If you like shipping more than waiting, this is the team.