Top 5 System Design Interview questions at Apple
As a hurdle for a senior engineering role at Apple, the System Design Interview can be career-defining. In a world increasingly dependent on distributed systems, the System Design Interview is indispensable for senior roles, as it assesses your ability to design and refine distributed systems.
Having conducted hundreds of System Design Interviews myself at Meta, Microsoft, and now, Educative, I know that the System Design Interview can be intimidating for many talented engineers — but the right amount of targeted interview prep can help you stand out against the competition.
To help you prepare, I'll walk you through 5 popular questions asked at the Apple System Design Interview:
Design the Apple Music system
Design the Apple Maps system
Design the AirTag tracking system
Design an application tracking system
Design the App Store system
Because preparing for common questions isn't enough, I'll leave you with some tips to display the traits Apple is looking for (in the Apple interview, it's essential to show your culture fit and passion for innovation).
Let's get started.
What happens in the System Design Interview at Apple?#
The interview process and focus depends on the division interviewing you. For example, the cloud infrastructure team might ask about the underlying platform that supports applications and services, while the AI and ML team might ask about infrastructure for training AI and ML algorithms.
That said, you can expect this general flow in Apple's System Design Interview:
Problem statement: You'll be asked a high-level problem or a real-world scenario that requires designing a system or a system component.
Requirements: After asking clarifying questions to understand goals and constraints, you'll identify requirements, such as high availability, reliability, or cost-effectiveness.
High-level design: Draw a high-level design that represents the system‘s major components, and how they interact together to meet requirements.
Throughout the interview, you should communicate your thought process, consider alternative solutions, and discuss trade-offs you make around your design decisions.
Deep dive: Dive deeper into specific components of the design and underlying algorithms. This could involve detailing the design of an API, discussing database schema, explaining how to maintain data consistency, or how the system will handle failures and ensure reliability.
Addressing scalability and performance considerations: This includes discussing load balancing, partitioning data, optimizing response times, and ensuring the system can handle increased traffic without degrading performance.
Discussion and Q&A: You'll evaluate and discuss your design with the interviewers. While this is a good time to justify your design choices, it's crucial to show a collaborative spirit by being open to feedback and challenges against your design.
Note: If you are new to System Design in general, check out the Educative blog for the beginner’s guide to System Design Interviews at FAANG/MAANG.
5 common System Design questions at Apple#
For each problem, we'll consider the functional and nonfunctional requirements and high-level design.
1. Design the Apple Music system#
Apple Music is an audio streaming service developed by Apple that offers access to a vast library of music, curated playlists, radio stations, and more.
Requirements for the Apple Music system#
Functional requirements#
Music streaming
Uploading music
Payment management
Offline playback
Music library management
Nonfunctional requirements#
Scalability
Reliability
Performance
Security
System Design and Workflow of the Apple Music system#
Initial user requests and load balancing#
In the Apple Music system, when users make a request, such as searching for a song or streaming music, the request first hits a load balancer. The load balancer distributes incoming traffic to various web servers, which handle user requests and serve dynamic content. Web servers then communicate with application servers to process user interactions, manage playlists, and handle authentication and authorization.
Music upload and transcoding#
When a user uploads new music, the upload service stores the raw audio files in the blob store, a scalable and efficient storage solution for large files. Once uploaded, a transcoding service converts the raw files into various formats and bitrates to ensure compatibility and optimal streaming quality across different devices. The transcoded files are then cached and served through a content delivery network (CDN) to minimize latency and improve streaming performance.
Streaming and data management#
For streaming, the streaming service retrieves the necessary audio files from the blob store and delivers them to the client via the CDN. The system integrates with a payment system to manage user subscriptions and transactions.
User data (preferences and playlists) is stored in a user data database.
Song metadata (artist information and album details) is maintained in a separate song metadata database.
This architecture ensures efficient handling of user requests, seamless playback, and robust music content and user data management.
Note: To understand the detailed design, you can review an enhanced version of a streaming system like YouTube or Netflix.
2. Design Apple Maps#
Apple Maps is a mapping and navigation service developed by Apple. It provides various location-based services, such as real-time navigation, location search, and real-time notifications.
Requirements for the Apple Maps system#
Functional requirements#
Real-time navigation
Location/area search
Route search/finder
Route planning
Real-time notification
Nonfunctional requirements#
Scalability
Reliability
Low latency
Usability
System Design and workflow of the Apple Maps system#
Handling user requests and load balancing#
In the Apple Maps system, client requests for location-based services initially pass through a load balancer. The load balancer distributes traffic across multiple backend services to ensure scalability and reliability.
Routing and location services#
Route finder service: Calculates optimal paths using real-time and historical data. It relies on the graph processing service to perform complex calculations on the road network graph stored in the graph database, which contains detailed information about roads, intersections, and travel times.
Location finder service: Provides the user’s current location or identifies the location of a specified point of interest. This information is crucial for generating accurate navigation instructions, which are then handled by the navigator service.
Area search and real-time updates#
The area search system queries nearby locations using the graph database and third-party road data sources. A pub/sub system broadcasts real-time updates like traffic alerts or road closures, ensuring updated routing and navigation.
The high-level design of the Apple Maps system is depicted below:
Note: To understand the detailed design, you can review the detailed design of Apple/Google Map.
3. Design the AirTag tracking system#
The AirTag tracking system is a device and service ecosystem developed by Apple that allows users to locate and track their items. An AirTag is a small, coin-shaped device that can be attached to items such as keys, bags, or other personal belongings.
Requirements for the AirTag tracking system#
Functional requirements#
Device registration and pairing
Location tracking
Lost mode activation
Notification
Historical and real-time data analysis
Nonfunctional requirements#
Scalability
Reliability
Performance
Security
System Design and workflow of the AirTag tracking system#
Initial device communication and load balancing#
The AirTag device broadcasts its presence using Bluetooth and Ultra-Wideband (UWB).
Nearby finder devices detect this signal and use their GPS capabilities to determine the AirTag’s location, sending this data to Apple’s servers.
The owner device, which has paired with the AirTag, receives location updates and battery status from the AirTag and sends this data to the backend services through the load balancer.
Location updates and lost mode activation#
Location update service: Processes new location data and updates the database.
Lost mode service: Activates when an AirTag is marked as lost, updating databases and triggering the notification service to alert the user.
Battery management and data analysis#
The battery management service monitors battery status and sends low-battery alerts via the notification service. The data analytics service periodically accesses data from the databases to analyze usage patterns, battery performance, and system metrics, generating reports that can inform system improvements and user insights.
This interconnected system ensures reliable tracking, efficient data management, and timely user notifications.
The following is the high-level design of the AirTag tracking system:
Point to Ponder
Shouldn’t a battery management chip be inside the AirTag device instead of a separate service?
4. Design an application tracking system (ATS)#
Requirements of application tracking system#
Functional requirements#
Current jobs search
Application submission
Job management
Interview scheduling and tracking
Nonfunctional requirements#
Scalability
Reliability
Consistency
Security
System Design and workflow of the application tracking system#
User interaction and load balancing#
In the ATS, clients interact through a user interface to search for jobs, submit applications, or schedule interviews. Requests pass through a load balancer to distribute traffic to application servers for efficient handling.
Key services and data management#
Authentication and authorization services: Handles user login and access control, ensuring that only authorized users can access specific features and data within the system. This service retrieves users’ data from the SQL database for authentication.
Application submission service: Once authenticated, users submit applications which are processed and stored in the file system.
Resume parsing service: Extracts and updates data in the metadata database for efficient job search.
Job management and notifications#
The job management service then manages job applications, tracking their status and integrating with the search and filtering applications to help recruiters find suitable candidates based on various criteria.
The interview scheduling and tracking service coordinates interview arrangements and keeps track of scheduling details.
A pub/sub system provides real-time updates to users like status changes or interview reminders, ensuring smooth and timely communication.
A high-level design of the application tracking system is given below:
5. Design the App Store system#
Apple’s App Store is a platform for mobile apps on iOS and iPad. It serves as a marketplace where developers can distribute their apps to users, and users can browse, purchase, download, and update applications for their Apple devices.
Requirements for the App Store system#
Functional requirements#
App search
App update, download, and installation
Payment management
App uploading and management
App recommendations
Nonfunctional requirements#
Scalability
Reliability
Consistency
Low latency
Security
System Design and workflow of the App Store system#
User interaction and traffic distribution#
Clients use a user interface for browsing and downloading apps. Initial requests, like app searches or purchases, are handled by a load balancer. The load balancer distributes incoming traffic across multiple application servers to ensure the system can efficiently handle high volumes of concurrent requests.
Core services and data storage#
Authentication and authorization: Verifies user identity for app access and purchases.
Search and filter apps service: Helps users find apps based on categories or ratings.
App catalog and download service: Manages the app catalog, enabling downloads and updates.
App uploading service: Handles submissions, storing apps in the blob store with metadata in the metadata database.
Payment and notifications#
The payment gateway manages transactions securely, while the pub/sub system delivers real-time notifications, such as app updates or purchase confirmations.
The following illustration shows the high-level design of the Apple App Store system.
If this is your first System Design Interview for a senior level position, you should know that the expectations will be different than if you've interviewed as a junior candidate. To learn more, check out the Educative blog comparing designing YouTube junior, senior, and principal engineers.
Acing the System Design Interview at Apple#
You may not encounter the exact questions we covered today, so don't stop here for System Design Interview prep.
To cover your bases, be sure to:
Have a strong grasp of System Design fundamentals and concepts
Practice and refine your communication through mock interviews
Prepare to show your culture fit
Unlike other technical interviews, displaying your culture fit is important during the System Design Interview. Apple’s CEO, Tim Cook, shared that he looks for candidates with the following traits: Collaboration, Creativity, Curiosity, and Expertise.
You can display these traits in your System Design Interview by:
Researching different systems created by Apple. They may ask questions relevant to the existing systems or devices. (Expertise)
Being an active participant in the interview. Ask clarifying questions. Show them your creativity. (Curiosity and Creativity)
Discussing past successes and experiences. Your unique story is often what interviewers remember you by. (Experience)
Showing your ability to collaborate and communicate effectively. These are the skills that make you a great team member. (Collaboration).
Check out Educative's Interview Prep resources to find various courses on System Design Interview Prep, get feedback with AI Mock Interviews, and prepare for every round that's coming your way.
Good luck interviewing!
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