Principal Android Engineer

Job Description:

Rakuten International is a division of Rakuten Group, Inc., a Japanese global technology leader in services that empower individuals, communities, businesses and society. Headquartered in San Mateo, California with more than 4,000 employees worldwide, the Rakuten International business portfolio includes market leaders in e-commerce, digital marketing, advertising, communications and entertainment. We create products and services that provide exceptional value by aligning members and the businesses that want to engage them in a shared community.

Rakuten is the most rewarding way to shop, giving millions of members Cash Back when they buy from their favorite brands. As a leading shopping platform, Rakuten partners with thousands of top brands across apparel, beauty and wellness, grocery, travel, on-demand services, subscriptions, and dining, helping members save on everyday purchases. Since 1999, Rakuten members have earned more than $4.6 billion in Cash Back, making it the largest Cash Back platform of its kind. Learn more at Rakuten.com.

• Job Summary:
• We are seeking a visionary Principal Android Engineer to lead the evolution of our client application architecture and platform capabilities. You’ll define and drive the technical direction for Android across core frameworks, dynamic rendering systems, and design system integrations that power scalable mobile experiences.

You will collaborate closely with product managers, designers, and engineering teams to deliver high-performance, accessible, and localized mobile applications. As a technical leader, you will shape reusable application frameworks, UI component systems, and SDK integrations that enable consistent and high-quality implementations across multiple client platforms.

This high-impact position influences architectural standards, mentor engineers, and champion best practices in performance, accessibility, localization, multi-region capabilities and platform scalability. If you are passionate about building foundational mobile platforms, enabling engineering excellence, and shaping the future of large-scale mobile applications, we want you on our team.

In this role, you will design, develop, and maintain software applications to meet user needs and business objectives. You will analyze requirements, write clean and efficient code, and collaborate with cross-functional teams to deliver scalable and user-friendly applications. Your role will involve debugging and improving existing applications, ensuring optimal performance, and integrating new features to enhance functionality. With a strong foundation in application development and problem-solving skills, you will contribute to creating innovative solutions that align with organizational goals.

Key Responsibilities:

Advises senior management of strategic opportunities and risks associated with emerging technologies and industry trends.

Applies advanced knowledge of software engineering principles to develop and implement solutions that meet complex business objectives.

Conducts advanced research and analysis to identify innovative approaches for improving system performance and scalability.

Consults on critical design and development decisions to ensure alignment with organizational strategy and compliance standards.

Devises robust architectures and frameworks that optimize application functionality and future scalability.

Leverage and guide adoption of modern AI and machine learning strategies, including generative AI and intelligent automation, to enhance developer productivity, optimize application capabilities, and drive innovation in mobile platform solutions.

Directs team to implement best practices and adhere to established standards for coding, testing, and deployment.

Define standards and best practices for API integration and client-service communication to ensure scalability, reliability, and maintainability across mobile platforms.

Drives cross-functional collaboration to ensure successful execution of high-priority projects.

Facilitates knowledge-sharing sessions to mentor less-experienced team members and advance organizational technical expertise.

Masters emerging technologies and adapts them to enhance the organization’s competitive position in the market.

Define and drive the long-term Android platform technical roadmap aligned with product strategy and business objectives.

Establish and participate in architecture governance and technical design review processes to ensure consistency, scalability, and adherence to engineering standards across client platforms.

Evaluate, pilot, and guide adoption of emerging technologies, frameworks, and tools that improve platform capabilities and developer productivity.

Identify, prioritize, and mitigate technical risks and architectural debt that could impact platform scalability, performance, and maintainability.

Drive improvements in developer experience (DX) through better tooling, automation, documentation, and reusable platform capabilities.

• Qualifications:
• To perform this job successfully, an individual must be able to perform each essential duty satisfactorily. The requirements listed below are representative of the knowledge, skill, and/or ability required. Reasonable accommodations may be made to enable individuals with disabilities to perform the essential functions.

Expert in Android SDK, Android Studio, Kotlin, and Java.

Deep understanding of Android OS concepts, UI/UX and security best practices, and performance optimization.

Strong knowledge of architectural patterns such as MVVM, MVP, or Clean Architecture.

Experience with modularization, dependency injection (e.g., Dagger or Hilt), and reactive programming (e.g., RxJava, Coroutines).

Experience building large-scale, event-driven architectures using tools like Event Bus, LiveData, RxJava, or Coroutines/Flows

Expert with XML Views/Jetpack Compose.

Strong background in Agile methodologies, continuous improvement, and process automation.

Experience in coordinating with cross-functional teams to drive process improvements and ensure product quality.

Expertise in writing robust, maintainable, and testable code. Experience with code reviews, debugging, unit testing (using frameworks like JUnit, Robolectric), and UI testing (using Espresso).

Experience with global app deployments, feature flags, A/B testing, analytics and working in a monorepo environment

Portfolio of published applications on GitHub and/or the Play Store.

Experience leveraging AI tools and technologies to optimize or redesign engineering workflows, delivering measurable improvements in efficiency, quality, or productivity.

Familiarity with responsible and ethical AI practices, including risk assessment, bias mitigation, and ensuring quality, transparency, and accuracy in AI-assisted solutions.

Commitment to continuous AI skill development, including experience with prompt and context engineering, AI-assisted development workflows, or agent-based systems, and staying current with emerging AI technologies.

Strong problem-solving and communication skills.

Experience with Design Systems.

Knowledge of emerging technologies in mobile development is a plus.

Minimum Requirements:

Bachelor’s or Master’s degree in Computer Science, Software Engineering, or a related field.

Solid written and verbal communication skills.

15+ years of software engineering experience, including leadership roles.

• Five Principles for Success
• Our worldwide practices describe specific behaviors that make Rakuten unique and united across the world. We expect Rakuten employees to model these 5 Shugi Principles of Success.

• Always improve, Always Advance - Only be satisfied with complete success - Kaizen
• Passionately Professiona l - Take an uncompromising approach to your work and be determined to be the best
• Hypothesize - Practice - Validate – Shikumika - Use the