Canonical Software Engineer Interview Questions + Guide in 2025

Canonical is a technology company known for developing the Ubuntu operating system. Founded in 2004, it continues to drive advancements in Linux and open-source software.

If you’re a software engineer passionate about open-source software and have some experience with Linux, Python, and Golang, you’ll fit right in.

The following guide includes the process, commonly asked Canonical software engineer interview questions, and our handpicked strategies to boost your chances of landing your dream role.

Canonical has a pretty detailed interview process that consists of the following stages:

Step 1: Written Interview

Once your CV is selected, you’ll receive an e-mail from the hiring manager with a list of questions. These are designed to assess your personality and work experience and fall under the following categories:

• Education: This is to understand your interests in high school and university.
• Engineering: You’ll be asked questions like “Describe your experience with Linux-based software development” and “Outline your thoughts on performance in software development.”
• Industry leadership: They’ll want to know about your participation in industry events and conferences or if you blog about your engineering journey.
• Context: The questions here aim to draw out your views of Canonical as a company and how well your aspirations align with them.

Since there are around 38 questions, answer concisely. You’ll have the opportunity to elaborate more during the interviews.

Step 2: Aptitude Test

This step involves a personality assessment and IQ test. The questions are pretty standard, and the test will take about an hour to complete.

Step 3: Culture/HR Interview

Then, you will be invited to a video call with someone who isn’t on the team you’ve applied to. You will be asked a series of behavioral questions to understand your fitness for the company.

Step 4: Technical Interviews

After assessing your cultural fit, you will enter a series of technical interviews (usually 3 rounds). You may also be asked to solve a take-home assignment and discuss the solution in the following round.

Step 5: Manager Interviews

In the late-stage rounds, you’ll speak to your future teammates and managers. This round is designed to assess how well you’ll fit in the team and for you to ask any questions about the work and team culture.

Software engineers should expect questions on various engineering concepts, with an emphasis on Python and algorithms. Be prepared to answer questions on the fundamentals of operating systems and whatever language/framework is relevant to your role.

Read on for our handpicked practice problems for the Canonical software engineer interview. For best results, try answering the question yourself before looking at our hints or clicking on the solution!

1. Why do you think your personality matches with the company culture?

Canonical values community involvement, open communication, and a passion for open-source projects. This question assesses whether your work style aligns with these values.

How to Answer

Read up on Canonical’s culture and relate their values to your personal experiences.

Example

“My enthusiasm for technology and open-source software has always been a driving force in my career. In college, I organized coding workshops and contributed to several open-source projects on GitHub, which made me realize the value of collaboration. I’m someone who thrives on teamwork and is excited to solve complex problems through shared effort.”

2. Why do you want to join Canonical?

Interviewers will want to know why you chose the software engineer role at Canonical. They want to establish whether you’re passionate about the company’s culture and values or your interest is more opportunistic.

How to Answer

Demonstrate knowledge of Canonical’s work, culture, and the opportunities that appeal to you. Focus on specific aspects of Canonical that attract you, such as its innovative approach to technology.

Example

“Canonical’s leadership in developing Ubuntu, a platform I’ve personally used and contributed to, has always inspired me. The idea of working on projects that have a global impact, alongside a team that values collaboration and open innovation, is incredibly motivating.”

3. What kind of software projects have you worked on before?

Since Canonical works on a wide array of software projects, from operating systems to cloud computing and IoT, understanding a candidate’s background helps in assessing where they might fit within the company’s ecosystem.

How to Answer

Provide a concise overview of your most significant projects and quantify the impact of your contributions.

Example

“In my previous role, I worked on a cloud-based SaaS platform designed to streamline business operations for small to medium-sized enterprises. I was involved in backend development, primarily using Python and Flask, and I contributed to developing several APIs to facilitate seamless integration with third-party services. Additionally, I volunteered in an open-source project aimed at improving digital literacy in underdeveloped regions, which was built on a Linux-based system. These experiences have honed my skills in cloud computing, API development, and working with open-source software.”

4. Tell me about a time when your colleagues did not agree with your approach.

Navigating disagreements is key to contributing to the company culture and product development.

How to Answer

Describe a conflict in which you played a role in finding a mutually beneficial outcome. Highlight what you learned from the experience, showing your willingness to adapt and grow.

Example

“I once had a conflict with a co-worker over prioritizing project features. To resolve it, I set up a one-on-one to discuss our viewpoints and come to an agreement. We decided to consult other team members and gather more user data to make an informed decision. This experience helped me appreciate the importance of empathy and flexibility in teamwork.”

5. Please explain how you have kept up with current market problems in the tech industry.

Canonical values employees who have a keen understanding of market dynamics and challenges the industry faces.

How to Answer

Describe how you stay updated, such as following reputable tech news outlets, participating in community forums, attending conferences, or taking courses. Highlight how this continuous learning has informed your work.

Example

“I regularly follow tech news platforms like TechCrunch and Ars Technica, and I’m an active member of GitHub and Stack Overflow. These interactions allow me to contribute to projects that address evolving challenges in the industry. For instance, learning about the increasing importance of cloud security led me to take a specialized course in cybersecurity. I used the learnings to enhance security features in a project I was working on.”

6. Given an array filled with random values, write a function to rotate the array by 90 degrees clockwise.

As a software engineer, understanding multidimensional arrays is important to design any system that requires oriental manipulation.

How to Answer Explain the concept of matrix rotation and the steps involved, which is usually transposing the matrix and then flipping it horizontally.

Example

“This can be done using the NumPy library in Python, which efficiently handles arrays. The function will transpose and flip the input matrix horizontally, effectively rotating it 90 degrees clockwise. It’s efficient and works well with matrices of any size.”

7. Write a program that checks if an integer is a vampire number.

Vampire numbers are a fun and interesting problem that tests understanding of number properties, iteration through possibilities, and string manipulation, which are relevant skills in many software development tasks.

How to Answer

Describe the strategy for identifying vampire numbers. It involves checking if an integer can be factored into two numbers (fangs) of equal length, where the digits of the fangs can be rearranged to form the original number.

Example

“My program would first verify that the number has an even number of digits; if not, it cannot be a vampire number. Next, it would generate all possible pairs of factors (fangs) that are each half the length of the original number. For each pair, the program checks if rearranging the digits of the two fangs can produce the original number. This involves converting the numbers to strings, sorting the digits, and then comparing the sorted string of the original number with the concatenated, sorted strings of the fangs. It’s important to iterate efficiently, only considering fang pairs that meet the criteria (e.g., excluding pairs where both fangs end in zero, as this would not lead to a valid vampire number). If any pair of fangs satisfies these conditions, the number is a vampire number.”

8. Implement the Fibonacci algorithm in three different methods: 1. recursively, 2. iteratively, and 3. using memoization.

The Fibonacci sequence is a classic problem in software engineering interviews. Canonical needs to implement scalable solutions and your approach to this problem will reveal how well you understand this.

How to Answer

Demonstrate your understanding of the trade-offs between simplicity (recursion), efficiency (iteration), and optimization (memoization). Explain how each approach can be used in different scenarios based on computational resources and execution time.

Example

“A recursive solution involves a function calling itself with a smaller subset of the problem until it reaches a base case. This method is straightforward but can lead to significant inefficiencies due to repeated calculations. The iterative approach calculates each Fibonacci number sequentially, starting from the base cases and building up to the desired number by looping from 0 to n. This method is more efficient as it doesn’t involve repeated calculations or deep call stacks. Memoization optimizes the recursive solution by storing previously calculated Fibonacci numbers in a data structure during the function’s execution. When the function is called again with the same input, it first checks if the result is in the storage to avoid recalculating, which reduces the number of computations needed.”

9. You are given an array of string tokens that represent an arithmetic expression in a Reverse Polish notation. Evaluate the expression.

Evaluating RPN expressions requires an understanding of stacks and post-order traversal logic, which are crucial for parsing expressions or developing features like calculators, compilers, or interpreters in software development.

How to Answer

Discuss using a stack to evaluate the expression. Explain how you would iterate through the tokens array, pushing numbers onto the stack until an operator is encountered.

Example

“I would use a stack to store operands. While iterating through the array of tokens, I would push any numbers I encounter onto the stack. When I come across an operator, I’d pop the two most recent numbers off the stack, apply the operator (being careful to maintain the correct order), and then push the result back onto the stack. After processing all tokens, if the expression is valid, there should be exactly one number left on the stack, which is the result of the expression.”

10. You’re given a list of sorted integers in which more than 50% of the list is comprised of the same repeating integer. Write a function to return the list’s median value.

This question tests your understanding of statistics and optimization efficiency based on a given set of conditions.

How to Answer

Mention how the presence of a majority element (more than 50% occurrence) affects the median’s location. With this information, focus on optimizing the median-finding process, highlighting that the median must be the majority element itself due to its frequency and distribution.

Example

“Given the list is sorted and contains a majority element (an element that appears more than 50% of the time), the median will always be this majority element, regardless of whether the list length is odd or even. This is because, in a sorted list, the middle element(s) that determine the median must be part of the majority element’s sequence due to its dominance. Therefore, my function would not need to inspect each element to find the median. Instead, it could directly return the value at the middle index of the list.”

11. What is the main advantage of Javascript?

Knowing you have a grasp of different programming languages and their strengths is essential for a company like Canonical that works on diverse software projects.

How to Answer

Highlight JavaScript’s ability to run on both the client and server side (thanks to environments like Node.js) and its role in enabling dynamic content and interactive web applications.

Example

“As the only programming language natively understood by web browsers, it allows developers to create interactive and dynamic web applications. JavaScript’s execution on both the client and server sides, particularly with the advent of Node.js, enables a unified language for full-stack development. Moreover, JavaScript’s extensive ecosystem, including frameworks like React, Angular, and Vue.js, empowers developers to build complex applications efficiently.”

12. Write a function to sum two strings together without directly converting them to integers.

Your ability to manipulate strings and understand numerical operations will be instrumental in developing and debugging Canonical’s software products.

How to Answer

Explain the strategy of iterating over both strings from the end to the beginning, simulating the addition process digit by digit, much like how you would add numbers on paper. Highlight edge cases, such as different string lengths and leading zeros.

Example

“I’d start by initializing an empty result string and a variable to keep track of the carry, which is initially 0. Then, I’d iterate through both strings from the last character to the first, adding the numeric value of each digit (after converting them from their character representation) along with any carry from the previous step. If the sum of two digits plus the carry is greater than 9, we update the carry to 1 for the next iteration and subtract 10 from the result to keep it a single digit. Otherwise, the carry is set to 0. Since we’re adding the digits in reverse order, the final step is to reverse the result string before returning it.”

13. What are Go channels, and how are channels used in Golang?

If you join Canonical, you’ll need to work on Golang quite a bit, so the interviews will test your grasp of the program’s basic concepts.

How to Answer

Mention the types of channels (buffered and unbuffered) and their respective use cases.

Example

“Channels in Go are used for communication between goroutines to enable safe data transfer. Unbuffered channels facilitate direct hand-offs, pausing the sending goroutine until the receiving one is ready, which is useful for ensuring tasks are synchronized. Buffered channels, however, allow sending messages without waiting, up to a certain capacity, useful for managing work queues and asynchronous processing.”

14. Write a function to merge two sorted lists into one. What would its time complexity be?

This question tests your algorithmic thinking and understanding of time complexity, fundamental skills for developing efficient, scalable software.

How to Answer

Explain the strategy of using two pointers to iterate through the lists, comparing elements and adding the smaller one to the new list until one list is exhausted, then appending the remainder of the other list.

Example

“I’d use a two-pointer approach, starting at the beginning of each list. If one list is exhausted before the other, I would append the rest of the remaining list to the new list. The time complexity of this function is O(n+m), where n and m are the lengths of the two lists because each element in both lists is visited exactly once.”

15. What is the role of the “init” function in Go?

This question aims to assess your understanding of Go’s initialization patterns, which are crucial for setting up programs correctly.

How to Answer

Emphasize its automatic execution before the main function starts and its common uses, such as initializing application components or validating the environment.

Example

“The init function in Go is a special function that automatically runs before the main function. Its main role is to initialize program components, such as setting up configurations, initializing global variables, or performing startup checks. This is particularly useful in complex applications where certain conditions or settings must be established before the application starts running.”

16. Write a Python function to return the maximum profit from buying and selling a stock.

Understanding how to maximize profit in a given scenario using algorithmic thinking is key in many software engineering tasks, including financial analysis and data processing.

How to Answer

Explain the logic behind your approach, discussing how you track the maximum profit at each stage (after each buy and sell) and how the problem resembles optimizing decisions in a changing environment. Briefly mention the importance of efficient and scalable code.

Example

“In this function, I will use dynamic programming to keep track of the profits after each buy and sell action. The function iterates through each price, updating the potential profits. This approach ensures we consider the best possible outcome at each stage, which is crucial for optimizing profits in a dynamic setting like stock trading or managing real-time data.”

17. Can you explain the “Shift left to reduce failure” concept in DevOps?

You will need to have a grasp of DevOps practices and principles, as these are necessary to improve the quality of software through early involvement in the development lifecycle.

How to Answer

Describe the concept and its benefits, such as identifying and addressing issues earlier and reducing the cost and time to fix bugs.

Example

“The ‘Shift left to reduce failure’ concept in DevOps emphasizes the early integration of testing and quality assurance into the software development process. By ‘shifting’ these activities to the left, meaning earlier in the development lifecycle, teams can identify and address issues much sooner, which significantly reduces the likelihood of major failures later on.”

18. Given a list of sorted integer lists, write a function to create a combined list while maintaining sorted order without importing any libraries or using sort functions in Python.

Software engineers need to understand concepts like merging sorted integer lists for applications such as streamlining logistics and scheduling tasks.

How to Answer

Go through a step-by-step approach to merging lists while maintaining sorted order. Focus on how you iterate through each list, compare elements, and choose the smallest element at each step to add to the final merged list. Highlight the efficiency of your approach.

Example

“In my solution, I would maintain an array of pointers to track the current element in each list. At each step, I’d look for the smallest element in each list and add it to the merged list. This way, we effectively merge all lists while maintaining their sorted order. This approach is efficient because it minimizes comparisons and eliminates the need for an external sorting library. Each iteration involves only a comparison of the heads of the remaining lists.”

19. How would you choose a Linux distribution?

This question tests your familiarity with the Linux ecosystem, including the strengths and purposes of different distributions.

How to Answer

Outline key factors to consider, such as the specific needs of the project. Mention the importance of evaluating the distribution’s update and support policy, compatibility with hardware or software requirements, and the learning curve for new users.

Example

“Choosing a Linux distribution depends on several factors, starting with the project or organization’s specific needs. For instance, if stability and long-term support are priorities, I’d consider distributions known for their robustness and extended support cycles, like Ubuntu LTS versions. For software development, a distribution with rapid updates and a wide range of available packages, like Fedora, might be more suitable. It’s also important to consider the hardware compatibility, especially for specialized or older hardware, and the level of community support available.”

20. Given a stream of numbers, select a random number from the stream with equal probability and O(1) space in the selection.

Canonical’s software solutions may require efficient algorithms that operate under resource constraints.

How to Answer

Discuss the Reservoir Sampling algorithm, which is designed to solve this exact problem. Emphasize that this method ensures each item has an equal chance of being selected by the time the stream ends, despite not knowing the stream’s length in advance.

Example

“The idea is to start by selecting the first number as the random number. Then, for every new number in the stream, the algorithm increments a counter representing the number of items seen so far. This approach also ensures that by the time you reach the end of the stream, each number has had an equal chance of being selected. The beauty of this method is its simplicity and the fact that it requires only a specified amount of space, as it keeps track of only one number and the count of numbers processed.”

21. Given the integer list nums with length n, create a function that converts each integer in the list into its corresponding Roman numeral representation.

Canonical values engineers who can handle a variety of programming tasks, including those that require algorithmic thinking and attention to detail. The problem requires you to design an efficient and accurate conversion function, showcasing your ability to work with number systems and string manipulation.

How to Answer

When answering, explain that the dictionary maps Roman symbols to integers in descending order, allowing the function to append symbols from largest to smallest. The function subtracts the largest possible value from the number repeatedly, appending the corresponding symbol each time until the number reaches zero.

Example

“In this solution, I would create a dictionary to map Roman symbols to their corresponding values, sorted from largest to smallest. I would then iterate through this dictionary, subtracting the largest possible value from the given number and appending the corresponding symbol to the Roman numeral string. This approach should efficiently convert any integer up to 1000 into its correct Roman numeral representation by ensuring that larger values are handled before smaller ones.”

22. Calculate the percentage of all total revenue made to date that was made during the first and last years recorded in the table.

By asking this, Canonical likely aims to evaluate your proficiency in managing data-driven tasks, attention to detail, and your ability to provide accurate, rounded outputs that are crucial for business reporting.

How to Answer

When answering this question, emphasize the logical flow of your approach. Start by explaining how you structured the query using common table expressions (CTEs) to isolate and calculate the total revenue per year. Highlight the use of window functions like ROW_NUMBER() to identify the first and last years of recorded data, and the SUM() function to compute total revenue. Finally, explain how you used these results to calculate and round the percentages for the first and last years in relation to the total revenue.

Example

“In tackling this problem, I would start by identifying the relevant revenue data for each year. To do this, I could use a common table expression (CTE) to segment the data and calculate the total revenue for each year. Then, I would determine which years represent the first and last recorded data points. Once I have these values, I should calculate the percentage of total revenue attributed to these specific years and ensure the result is rounded to two decimal places for clarity and accuracy.”

Here are some tips to help you excel in your interview:

Understand the Role and Responsibilities

Research the software engineer role at Canonical you’re applying for. Understand the key responsibilities and skills, and connect with current employees through LinkedIn for a better understanding.

Explore the specific role at Canonical through our Learning Paths to gain a comprehensive understanding of how your skills align with the requirements of this position.

Brush Up on Technical Skills

Revisit algorithms, data structures, system design principles, and coding techniques. Practice writing efficient, clean, and well-documented code. Remember that the focus is on assessing how you think rather than just your coding ability.

You can practice some cool engineering projects to bolster your resume.

Familiarize Yourself with Canonical’s Business Model

Gain a deep understanding of their products, market challenges, and technology stack. Consider how you could impact the business and ways you could contribute to solving real-world problems Canonical faces.

Practice Problem-Solving and Behavioral Questions

Prepare for behavioral questions using the STAR method. Reflect on your past experiences and practice articulating them concisely.

Visit our Interview Questions section to familiarize yourself with behavioral questions. It offers a wide range of practice questions to help structure your responses effectively using the STAR method.

Try a mock interview to test your current preparedness for the interview process.

Prepare Questions for the Interviewer

Make a list of questions about the work culture, challenges, and expectations, and show your eagerness to engage with the company’s ethos and future goals.

What is the average salary for a software engineering role at Canonical?

The average base salary for a software engineer at Canonical is $119,866, making the remuneration competitive for prospective applicants.

For more insights into the salary range of software engineers at various companies, check out our comprehensive Software Engineer Salary Guide.

Where can I read more discussion posts on the Canonical Software Engineer role on Interview Query?

Check out our discussion board, where Interview Query members talk about their experiences. You can use the search bar and filter for software engineering posts.

Are there job postings for Canonical Software Engineer roles on Interview Query?

We have software engineer jobs listed for Canonical, which you can apply for directly through our job portal. You can also filter by location, company, and position to see similar roles relevant to your career goals and skill set.

Succeeding in a Canonical software engineer interview requires solid technical skills and the ability to demonstrate your collaborative mindset in software development.

If you’re considering opportunities at other tech companies, check out our Company Interview Guides. We cover a range of companies, including Google, IBM, and Apple.

The key to your success is understanding Canonical’s culture of innovation and collaboration and thoroughly preparing technical and behavioral questions.

Check out more of Interview Query’s content, and we hope you land your dream role at Canonical soon!