The 7 Best Software Architect Interview Questions in 2023
What are the best software architect interview questions? Today, you get the top interview questions to ask your candidates – and find the right fit for your team. Read on!
Interviewing software architects
Software architecture refers to the high-level structure of a software system – similar to a blueprint, outlining system components, their interactions, properties, and design principles. It's key to meeting functional and non-functional requirements like performance, security, and scalability.
A software architect creates this blueprint. They design and document the software architecture, ensuring it fulfills user requirements and complies with constraints.
Architects also play a role in quality assurance, maintain the architectural integrity during development, provide technical leadership to the team, and guide the evolution of the software architecture to adapt to changing needs and technologies.
So, how do you identify the right software architect for your team? Here are the top interview questions and answers.
Beginner software architect interview questions
Let’s start with the top interview questions for junior software architects.
1. Can you explain what SOLID principles are and give an example of how you have used them in your previous projects?
SOLID is an acronym that stands for five design principles intended to make software designs more understandable, flexible, and maintainable. In short, it stands for:
Single Responsibility Principle (SRP): A class should have only one reason to change. It means a class should only have one job or responsibility.
Open/Closed Principle (OCP): Software entities should be open for extension, but closed for modification.We should be able to add new functionality to a module without changing its source code.
Liskov Substitution Principle (LSP): Subtypes must be substitutable for their base types. Basically, if a program is using a base class, it should be able to use any of its subclasses without the program knowing it.
Interface Segregation Principle (ISP): Clients should not be forced to depend on interfaces they do not use. It's better to have many specific interfaces rather than one general-purpose interface.
Dependency Inversion Principle (DIP): High-level modules should not depend on low-level modules. Both should depend on abstractions. Abstractions should not depend on details. Details should depend on abstractions.
In my previous role, I applied the Open/Closed Principle while working on an eCommerce application. There were several types of discount rules based on various factors like the time of purchase, type of product, and user status (new or returning). Instead of modifying the DiscountCalculator class every time a new rule was introduced, I made the class open for extension.
I achieved this by creating an IDiscountRule interface. Each new discount rule was a new class implementing this interface. The DiscountCalculator class was then modified to accept a list of IDiscountRule. For each purchase, it would run through this list to calculate the discount. This design made it easy to introduce new discount rules in the future without having to change the DiscountCalculator class.
2. Could you explain what a microservice architecture is and describe a scenario where it would be more advantageous to use than a monolithic architecture?
Microservice architecture breaks an application into smaller, independent services, each encapsulating a specific business function and communicating via APIs. This contrasts with monolithic architecture, where the application is a single unit.
A scenario favoring microservices might be a large eCommerce platform with different functionalities like user authentication, product management, order processing, and payment handling. Microservices allow independent scaling, technology selection, and faster updates for each function. However, they also present challenges in service coordination and data consistency that need careful management.
3. Can you describe what 'event-driven architecture' is and how it might be used in a real-world application?
Event-driven architecture is a design paradigm where the flow of the program is determined by events such as user actions, sensor outputs, or messages from other programs.
A real-world example might be a notification system in a social media app. When a user posts a new photo, it triggers an event. Subscribers to this event, perhaps users following the poster, receive a notification, effectively reacting to the event.
4. What is the Model-View-Controller (MVC) pattern and how can it be applied in web application development?"
The MVC pattern separates an application into three interconnected components. The 'Model' manages data and business logic. The 'View' handles user interface and presentation. The 'Controller' processes and responds to user input, manipulating the model as needed. In web development, MVC aids maintainability and testability, with, for example, a user's request being processed as a controller manipulating the model, which then updates the view.
Advanced software architect interview questions
What are the top interview questions for senior software architects? Here’s what you need to know.
5. Can you describe a time when you had to choose between a cloud-based solution and an on-premise one based on the client's needs? What factors did you consider and how did you ensure that the decision was aligned with the client's business goals?
The choice between cloud and on-premise is quite a common decision in software architecture, and it is often driven by the specific needs and constraints of the client. An instance that stands out in my mind is when I was working with a financial institution that was looking to digitize their banking services.
In terms of scalability, flexibility, and cost-effectiveness, a cloud-based solution would typically be the first choice. However, due to the highly sensitive nature of the data being handled, as well as stringent regulatory and compliance requirements, an on-premise solution appeared to be a better fit in this case.
The institution had already invested in secure and robust in-house infrastructure, and they were more comfortable having their data physically located within their premises. I understood their concerns about data privacy and regulatory issues, so I recommended an on-premise solution, while also taking steps to ensure that the system was scalable and resilient.
In making this decision, I spent a lot of time understanding the client's business objectives, their infrastructure, their risk tolerance levels, and their future plans. It was important to align the software architecture with these considerations to ensure that we delivered a solution that was fit for purpose and would support their business in the long term.
In the end, this comprehensive approach allowed us to build a system that was secure, reliable, and met all their requirements.
6. How would you approach migrating a large, monolithic system to a microservices architecture while ensuring minimal disruption to business operations?
Migrating a monolithic system to a microservices architecture is a challenging but rewarding endeavor. To start, I'd perform an exhaustive analysis of the monolithic application. This involves identifying modules or functionalities that can be broken down into independent, manageable services. It's often prudent to start with components that are relatively isolated, have clear domain boundaries, and bear few dependencies on other parts of the system.
Next, we'd focus on designing the corresponding microservice for the chosen functionality. This process encapsulates various aspects such as the core business logic, data storage, network communication, error handling, and other service-specific considerations. Once this microservice is fully developed and rigorously tested, it's time to deploy it. We would launch it alongside the monolithic system and reroute relevant requests from the monolith to the new service.
This process, commonly known as the 'strangler pattern,' allows us to progressively shift functionality to the new microservices architecture while maintaining the operations of the existing system.
Throughout this transition, maintaining strong lines of communication with the team and stakeholders is key. Everyone involved should understand the migration process and its impact on their work.
Additionally, ongoing monitoring of the new service's performance and usage in a production environment is vital. This ensures its functionality aligns with expectations before we proceed with the next phase of the migration.
Although this approach is time-intensive, it offers the advantage of keeping the system stable and operational, ensuring minimal disruption to business operations.
7. Could you discuss a situation where you had to balance trade-offs between system performance and system security? How did you approach the problem, and what were the results?
Balancing trade-offs between system performance and security is a common challenge in software architecture. I encountered a significant instance of this while working on a large-scale, data-intensive application for a client in the healthcare sector. Our system dealt with sensitive patient data, which mandated rigorous security measures. At the same time, performance was crucial due to the high volume of data being processed and the need for real-time insights.
My approach began with a thorough understanding of the business requirements and constraints. We needed to ensure high-level data encryption and robust authentication mechanisms to comply with data protection laws and industry regulations. However, these security measures added computational overhead and could potentially impact system performance. After evaluating several options, we decided to implement field-level encryption for sensitive data and used optimized algorithms to ensure minimal performance degradation.
Furthermore, we incorporated two-factor authentication to secure user access, which provided an additional layer of security without significantly affecting system performance.
As a result of this balanced approach, we were able to achieve our security objectives while maintaining acceptable performance levels. Regular audits and performance testing confirmed that the system met all regulatory requirements and performed well under load. The system was well-received by the client and is currently being used as part of their daily operations.
This experience highlighted the importance of understanding both business and technical constraints to make informed architectural decisions.
Over to you!
Those are the top software architect interview questions.
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