Senior Software Engineer, Mobile SDK - Tokyo,Japan

About Appier Appier is an AI-native Agentic AI as a Service (AaaS) company that uses artificial intelligence (AI) to power business decision-making. Founded in 2012 with a vision of democratizing AI, Appier’s mission is turning AI into ROI by making software intelligent. Appier now has 17 offices across APAC, Europe and U.S., and is listed on the Tokyo Stock Exchange (Ticker number: 4180). Visit www.appier.com for more information. About the Team We are a high-ownership, hybrid, and international team based in Taipei and Tokyo. We own all five SDK surfaces—iOS, Android, React Native, Flutter, and Web—which serve as the critical integration layer for enterprise clients with millions of daily active users. We operate with an AI-first engineering mindset within a Scrum/Gitflow workflow. We offer a flexible hybrid work model in Taipei/Tokyo CBDs, competitive benefits, and a dedicated budget for your AI tooling and continuous learning. About the role 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. About You [Minimum qualifications] 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. [Preferred qualifications] 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. Open to overseas candidates/Visa Support This position is open to based in Taipei, Taiwan or Tokyo, Japan. For international candidates, Appier's Japan office provides visa sponsorship to ensure a smooth transition to Japan. #LI-EZ1