Google iOS Engineer Interview Guide

Interview Guide Jun 11

Detailed, specific guidance on the Google iOS Engineer interview process - with a breakdown of different stages and interview questions asked at each stage

The role of a Google iOS Engineer

Google is renowned for developing groundbreaking technologies that impact the lives of billions of users worldwide. Their projects transcend web search and encompass areas such as information retrieval, distributed computing, system design, networking, security, artificial intelligence, natural language processing, UI design, and mobile development, including iOS.

For iOS engineers, Google is actively seeking individuals who are passionate about mobile app development, and they place a strong emphasis on fresh ideas and expertise in this field. As a Google iOS engineer, you'll work on mission-critical projects that align with Google's evolving needs, with the flexibility to explore different teams and projects as your career and Google's dynamic business evolve. You'll be part of a team shaping the future of iOS technology on a global scale.

In terms of compensation for iOS engineers, Google offers a competitive package:

  • Base Salary: $140,404
  • Stock Grant per year: $32,364
  • Bonus: $8,205

This results in an average total compensation of $180,973 annually.

Google iOS Engineer Interview Guide

The interview process for iOS engineers at Google comprises an initial phone screen with a recruiter—which serves as an introductory call to confirm your eligibility and availability for the role. 

Beyond that, you'll face two main interview rounds:

  • Technical Phone Screen
  • Onsite Rounds (up to 5)
Relevant Guides

Google iOS Engineer - Phone Interview


The technical phone interview for Google iOS Engineers typically consists of around 3 coding questions to be solved within a 45-minute time frame. During this interview, you'll be paired with a senior iOS engineer from Google.

The coding questions in this interview tend to focus heavily on computer science fundamentals, which means you'll be dealing with algorithms and data structures. While you might encounter a few iOS-specific questions, they aren't as common in this interview. The good news is that you're generally allowed to use either Objective-C or Swift for your solutions.

So, to prepare, make sure your CS fundamentals are strong and you are comfortable in both Objective-C and Swift.

A great way to prepare for the technical phone interview with Google as an iOS Engineer is to practice with mock interviews, especially with experienced Google iOS Engineers. You can find such experts on platforms like Prepfully, where you can book 1:1 sessions directly with them.

Google iOS Engineer - Onsite Round


If you make it past the initial round, you'll have 5-6 interviews back-to-back.

Roughly half of these interviews will focus on algorithms and data structures, but the questions will be more challenging compared to the phone interviews. So, be prepared to tackle complex problems and demonstrate your problem-solving skills.

The other half will be iOS-specific and require a good understanding of the domain. You should have a good grasp of how computer science fundamentals apply to iOS. Topics that might come up include:

  • Concurrency in iOS.
  • iOS's memory management model and its distinctions from other platforms.
  • Data storage methods used in iOS apps.
  • iOS networking and how it differs from desktop or data centre environments.

If you're interviewing for a senior-level position, one of your interviews will focus on systems design. You won't be expected to write code for this, but you'll need to design a reasonably complex system—like a distributed database for iOS apps. Deep knowledge of iOS, including its strengths and weaknesses, is crucial in this context. Interviewers will be looking for your ability to make engineering tradeoffs.

Here's a simplified breakdown of the interview rounds and questions you'll face:

  • Round 1: A coding question, typically related to String and Characters. For example, you might be asked to implement a function to reverse a linked list.
  • Round 2: Behavioural questions along with a coding question. For instance, you might be asked about a challenging situation you faced in a previous job and how you handled it. The coding question could involve sorting a list of integers.
  • Round 3: Another coding question, related to data structures and algorithms
  • Round 4: Some iOS knowledge questions along with a few coding questions. You might be asked to explain how memory management works in iOS and then tackle a few coding questions. For example, you could be asked to implement a feature in Swift, like parsing JSON data.
  • Round 5: An iOS design question where you'll need to implement the idea in Swift. For instance, you could be asked to design a system for a real-time chat application on iOS. You'd need to outline the components and architecture and possibly write Swift code to demonstrate your solution.

    This interview is quite similar to the one which occurs for the Doordash iOS Engineer.

Interview Questions

Interview Questions

  • You're tasked with designing a weather app for iOS. Describe the components, data sources, and user interface elements you would include, and explain the architectural pattern (e.g., MVC, MVVM) you'd use to build it.
  • How does URLSession differ from NSURLConnection in iOS? Describe the key features and advantages of URLSession, and when you would choose one over the other.
  • Explain the concept of Grand Central Dispatch (GCD) and when you would use it in an iOS application.
  • Given an array of integers, find the longest increasing subsequence. Explain the time and space complexity of your solution.
  • Add a debugging function to a view to print a tree of the view and its subviews. Follow-up: What information will be useful to print?
  • Find a view with a tag and return true if the view exists, false otherwise.
  • Implement a UI similar to the iOS calendar.
  • Suppose users might push a large number of UIViewControllers into a UINavigationController. How would you optimise it? Code it in Swift.
  • Discuss the difference between retain cycles and memory leaks in iOS. Provide an example of how you would avoid each of them.
  • Describe the purpose of Auto Layout and constraints in iOS user interface design. Create a simple scenario where you'd use Auto Layout to ensure proper layout on various iOS devices
  • Explain how Core Data works in iOS and discuss the advantages of using it for data storage in an app.
  • Design an image-browsing app.
  • How to convert a JSON file to a Dictionary type?
  • How to navigate between view controllers.
  • Transfer words to a digit panel.
  • Given a string, find the longest substring that contains 2 unique characters. Example: ""abcbbbbcccbdddadacb" => "bcbbbbcccb".
  • Implement parking garage parking and remove car functions.

Google iOS Engineer Roles and Responsibilities

Following are the roles and responsibilities of a Google iOS Engineer:

  • You'll write code for building products or systems.
  • You'll carefully check the code created by other engineers and provide helpful feedback to ensure it follows the right coding rules, is correct, can be tested, and runs efficiently.
  • You'll help create and update documents and training materials, making them better as products and programs change, based on what users tell us.
  • You'll be in charge of quickly identifying and fixing problems in products or systems by looking deep into where those problems come from and figuring out how they affect the hardware, network, and the overall quality.
  • You'll also play a part in improving documents and educational materials as things change because of products and programs.
  • You'll lead or join discussions with your colleagues and other people involved in projects to decide which technologies to use.

Google iOS Engineer Skills and Qualifications

Here are the skills and qualifications that a Google iOS Engineer must have:

  • You should have a Bachelor's degree or real-world experience that's equivalent.
  • You must have worked with software development for at least 2 years in one or more programming languages. If you have an advanced degree, 1 year of experience in a real industry setting is acceptable.
  • You should have 2 years of experience dealing with data structures or algorithms, either in school or in a tech job.
  • You need 2 years of hands-on experience with iOS app development.
  • You should have a Master's degree or a Ph.D. in Computer Science or a related technical field.
  • You must have 2 years of experience handling performance, large-scale system data analysis, visualization tools, and debugging.
  • Experience in creating technology that's accessible to a wide range of users is essential.
  • Proficiency in diagnosing and fixing code and system health issues, as well as software test engineering, is required.

Frequently Asked Questions