Senior Software Engineer, Mobile SDK - Tokyo,Japan

This is a hands-on, high-ownership senior role focused on building, maintaining, and architecting Appier's unified mobile growth stack. You will bridge engagement technologies with monetization and measurement solutions, ensuring high performance, cross-platform consistency, and privacy-first standards while driving AI-assisted engineering innovations.

Responsibilities

Architect Cross-Platform SDKs: Design features and developer-friendly APIs that behave identically across iOS, Android, React Native, Flutter, and Web, including hybrid JS-to-native bridges where needed; Feature Development & Privacy: Build high-value features for engagement (real-time tracking, push notifications, AI recommendations) and monetization/measurement, while ensuring strict support for evolving platform privacy requirements; Quality & Reliability: Lead root-cause investigations for complex client issues, maintain strict SLOs/crash-free rates, and manage CI/CD, automated testing, semantic versioning, and backward compatibility; AI-First Engineering & Leadership: Utilize AI coding agents daily to optimize design and code reviews, mentor engineers, and elevate team standards

Requirements

5+ years of software engineering experience, with 3+ years specifically building mobile SDKs or libraries for external/enterprise clients; Expert-level Swift (modern Swift Concurrency, async/await, actors) and/or Kotlin (Coroutines & Flow); Solid understanding of iOS/Android architecture, app lifecycles, background execution, and push notification systems (APNs, FCM); Deep expertise in mobile performance optimization (memory, battery, network efficiency) and implementing platform privacy requirements (e.g., Apple Privacy Manifests, Android Privacy Sandbox); Proficiency with CI/CD, automated testing, Git, and SDK versioning; Comfort using AI coding agents (e.g., Claude Code, Cursor, Copilot) as part of your daily workflow

Nice to have

Experience with cross-platform frameworks (Flutter or React Native) and Web technologies (JS/TypeScript, WebView bridges); Platform depth: iOS (SPM, app extensions, SwiftUI) or Android (Jetpack, Gradle, Play Store management); AdTech experience, including mobile ad SDKs, mediation platforms (AdMob, AppLovin MAX), and mobile attribution (SKAdNetwork, ATT); Experience in AI-augmented engineering (building MCP tools, agent skills, RAG pipelines) and on-device ML inference (Core ML, ML Kit); Experience mentoring engineers, setting technical standards, and managing client escalations end-to-end

Benefits

flexible hybrid work model in Taipei/Tokyo CBDs; competitive benefits; dedicated budget for your AI tooling and continuous learning; visa sponsorship for international candidates