A Mobile Engineer at eBay is responsible for building and optimizing the mobile experiences that power one of the world's largest and most vibrant marketplaces. With millions of active buyers and sellers globally, the mobile applications are the primary touchpoint for the majority of eBay's user base. Engineers in this role work on high-impact feature areas such as the eBay Selling flow, search and discovery, checkout, and next-generation interactive experiences like eBay Live.

Operating at this scale introduces unique technical challenges. You will design and implement robust, offline-first architectures, optimize network efficiency for global users, and ensure seamless state management across complex user flows. Whether you are developing natively in Android (Kotlin) or iOS (Swift), or building cross-platform solutions, your work directly impacts user engagement, conversion rates, and the overall reliability of the global marketplace.

At eBay, mobile development is not just about writing UI code; it is about building highly scalable, modular, and maintainable systems. You will collaborate closely with product managers, UX designers, and backend teams to deliver features that are robust, accessible, and highly performant. The team prioritizes clean architecture, comprehensive testing, and modern development practices to ensure the codebase remains agile and resilient.

The questions you will encounter during the eBay mobile interview process are designed to test your platform-specific expertise, architectural thinking, and collaborative skills. While these questions are representative of real interview experiences, they are structured to evaluate your fundamental engineering patterns rather than rote memorization.

Android Domain & Q&A

This category focuses on your deep understanding of the Android operating system, modern development libraries, and best practices.

• Explain the lifecycle of a ViewModel and how it survives configuration changes.
• How does Jetpack Compose handle state restoration, and what are the best practices for managing recomposition?

To succeed in the eBay mobile interview process, you must demonstrate a balanced mix of deep technical mastery, practical problem-solving skills, and a collaborative mindset. Your preparation should focus on the core areas that the hiring team evaluates.

Role-Related Knowledge – You must show a deep, native understanding of your chosen platform (iOS or Android). This goes beyond knowing syntax; you need to understand the underlying framework mechanics, memory management, concurrency models, and platform-specific UI rendering pipelines.

System Architecture & Design – At the senior and staff levels, eBay places a heavy emphasis on your ability to design clean, modular mobile systems. You should be prepared to discuss dependency injection, architectural patterns (MVVM, MVI, Clean Architecture), and how to scale mobile codebases across large, distributed teams.

Problem-Solving & Debugging – Unlike companies that rely solely on abstract algorithmic puzzles, eBay frequently evaluates your real-world debugging capabilities. You will be expected to navigate an existing codebase, identify performance bottlenecks or bugs, and implement clean, testable fixes under time constraints.

Culture & Values Alignment – eBay highly values collaboration, adaptability, and user empathy. You should be prepared to discuss how you work across functional boundaries, how you handle ambiguity, and how you keep the end-user experience at the center of your technical decisions.

The interview process for a Mobile Engineer at eBay is structured to evaluate both your immediate coding capabilities and your long-term architectural potential. The process typically spans three to four weeks from the initial application to the final decision, maintaining a steady and highly organized pace.

The journey begins with a recruiter screen and a hiring manager conversation, focusing on your background and alignment with the team's needs. Following this, you will enter the technical evaluation stages. For some roles, this includes an initial technical screen or a platform-specific coding assessment. The onsite loop consists of multiple focused rounds covering platform fundamentals, live debugging, system design, and behavioral discussions.

This timeline maps out the typical progression from your initial conversation with the recruiter to the final onsite rounds. By understanding this flow, you can pace your preparation, focusing first on core platform fundamentals before shifting your energy to architecture and behavioral alignment. Keep in mind that while the stages are standard, the exact order of technical rounds can occasionally shift depending on coordinator scheduling.

Platform-Specific Fundamentals

This area evaluates your deep technical understanding of either iOS or Android development. The interviewers want to see that you understand the "why" behind the frameworks you use daily, rather than just copying standard implementation patterns.

Be ready to go over:

• Concurrency and Threading – Managing background tasks, avoiding main-thread blockages, and utilizing modern concurrency frameworks safely.
• Memory Management – Understanding ARC, retain cycles, and memory leaks on iOS, or garbage collection patterns and reference types on Android.
• UI Rendering Pipelines – How the system draws views to the screen, managing layout passes, and optimizing complex layouts for smooth scrolling.
• Advanced concepts (less common) – Custom view drawing, custom transition animations, and low-level optimization of network serialization.

Example scenarios:

• "You are given a pre-written playground or scratchpad with a memory leak caused by a retain cycle. Identify the leak and refactor the code to resolve it."
• "Explain how you would implement a highly performant, infinite-scrolling list of media items, ensuring minimal memory consumption and zero frame drops."

Live Coding & Debugging

A distinctive part of the eBay mobile interview is the project-based debugging and implementation round. Instead of abstract algorithmic puzzles, you are often given a realistic, pre-written project in Android Studio or Xcode that contains existing bugs, incomplete features, or architectural flaws.

Be ready to go over:

• Code Navigation – Quickly understanding an unfamiliar codebase, tracing data flow between components, and identifying architectural patterns.
• State Handling – Correctly managing UI state during asynchronous operations, configuration changes, or network failures.
• Bug Identification – Finding logic errors, race conditions, or unhandled exceptions in the provided project.

Example scenarios:

• "An existing mobile project is failing to persist user input when the device rotates. Locate the issue in the ViewModel/Presenter and implement a robust state-saving solution."
• "Implement a missing API integration in an existing codebase, ensuring proper error handling and updating the UI state accordingly."

Mobile System Design

The system design rounds at eBay are highly practical and focused on mobile-specific constraints. You will need to design client-side architectures that are modular, testable, and capable of operating under unstable network conditions.