Software Architecture Interview Questions and How to Use Them
Software architecture is a broad, general plan that defines goals and guides the development of a software program. Most developers view such a plan as essential before any technical steps in creating a software program.
At the software architecture stage, all stakeholders in the proposed program have their say, negotiating the elements that will affect them most. Most of the questions raised are general: Will the software program be user-friendly? What is the overall organization of the system? Will users be able to adapt to it quickly?
And software developers might ask, “What security features will there be? Will it run at high speed? Will it be scalable? Easy to maintain and debug?”
These and related questions are the basis of communication among stakeholders so that an understanding is reached about their expectations. Taking the time to negotiate the elements of the system architecture is crucial in controlling the cost; and changes in system fundamentals once the work is underway can be hugely disruptive, as one feature change often impacts all the rest.
An expert in systems architecture is important for your organization’s software development team. As you might expect, that puts pressure on the hiring process.
Identifying the right software architecture interview questions can help you assess candidates for technical, varied, and subtle skills and characteristics. Let’s walk through some examples.
Software architecture design interview questions
Using code to define and solve problems is important, but so is imagination, understanding end users, and the ability to grasp workplace needs and capabilities.
The standard interview coding challenge tests what is already assumed: that a senior engineering candidate can write code and answer questions about a programming language. Plus, in-person meetings where your company’s senior engineers pose systems architecture interview questions eat up a great deal of time, especially since an average of 30+ candidates are typically interviewed.
Woven’s asynchronous technical assessment platform can help you vet candidates early in the interview process. That way, your time will be focused on diving into the interview questions below.
- As a senior architect, what are your most important skills and attributes?
- Can you describe how you delegate tasks to your team?
- How do you strike a balance between aesthetics and function?
- Describe a time you had a difficult client. How did you handle their demands?
- How do you ensure you stay on top of advancements in Architecture?
These senior developer interview questions assume code writing skills and knowledge of technical requirements of software architecture. Answers to these questions are the candidate’s self-report on their experience with problem-solving, teamwork, and technical communication.
Our assessment platform can also test these competencies in the context of real, job-related challenges.
Software architecture design interview questions
To bore into the design competencies of a candidate, use popular software architecture design questions (or systems design or “object-oriented analysis” questions). These do not require creating software, but instead ask a candidate to explain what a plan for the software might look like.
- How do you design the Vending Machine in Java? (Writing code for the operation of a vending machine for various products that accepts a range of coins.)
- How do you design a URL shortening service like goo.gl or bit.ly? (Taking a typically long URL and designing a service that would generate a shorter and unique alias for it.).
- How do you design a traffic control system? (Another classic system design question is programming for transition from one state to another—e.g., RED to GREEN.)
- How do you design a limit-order book for trading systems? (Designing a program used by stock exchanges to match buy and sell orders.)
- How do you design a website like Pastebin? (Planning a software program to paste text or code and then share a link to the code wherever you wish.)
Embedded system architecture interview questions
Another common way to assess candidates is by asking embedded system architecture interview questions.
- What is an embedded system in a computer system? (It is a computer system that exists within a larger system or machine, with a dedicated function.)
- What are the essential components of an embedded system? (Answers should name components of hardware, software, and the real-time operating system.)
- How are I/O devices classified for an embedded system? (The classifications are “serial” and “parallel,” each with several sub-classifications.)
- Why is an embedded system useful? (The embedded computer system can be a relatively cheap microprocessor that replaces potentially dozens of logic gates, timing circuits, and so forth.)
- Explain what real-time embedded systems are. (A real-time embedded system monitors, responds to, and controls something in the external environment to which it is connected by sensors and other input-output interfaces.)
Backend architect interview questions
Backend architecture should always be part of the system plan. It’s the coding behind the scenes that runs the system for the user on the front-end. These questions might be posed to a beginner getting their start in backend architecture:
- How would you manage Web Services API versioning? (In applications planning interface (API), versioning is how developers modify their API without having to stop the client from using the system.)
- How would you find the most expensive queries in an application? (Backend architects must worry about queries in a database that execute very slowly and can compromise the performance of an app.)
- What is CAP Theorem? (This question gets at an essential decision in backend programming based on the principle that consistency, availability, and partition tolerance (CAP) cannot all exist in the same distributed database system. The systems architect, in effect, must decide which two are important to the proposed software.)
Bonus questions for experienced engineers
There are plenty of resources available for low-level system design questions and object-oriented design interview questions. The following, however, are examples of the types of questions posed to candidates seeking an upper-level position:
- Can you name some metrics for measuring system performance? (Can the candidate explain different ways to measure a proposed system’s performance? For example: What will the user’s experience be of interacting with the system? How available will the system be in terms of uptime versus downtime? How much data travels through the system in a given time?)
- What is load balancing, and why is it important to system design? (How well does the candidate understand a key principle of system design: namely, load balancing and its contribution to the reliability of any system?)
- How would you design a tinyURL system? (A candidate with a solid foundation in design should be able to explain in detail how to create a shorter, unique URL after users enter a long URL. Candidates often are urged to prepare for interviews with a specific example such as providing a tinyURL system for entering hyperlinks into emails.)
Software architecture interview questions and answers
As you plan your interview questions for a software architect, it’s important to have an idea of the kind of answers you expect from a qualified candidate. There are plenty of online sites for interview questions, interview preparation, and automatic test grading that suggest ideal answers for engineers. They typically include software design interview questions and software architecture interview questions and answers.
Software scenario-based questions
Q1: What does “program to interfaces, not implementations” mean?
The suggested answer: Coding against interface means the client code always holds an Interface object which is supplied by a factory.
Any instance returned by the factory would be of type interface which any factory candidate class must have implemented. This way, the client program is not worried about implementation and the interface signature determines what all operations can be done.
This approach can be used to change the behavior of a program at run-time. It also helps you to write far better programs from the maintenance point of view.
Q2: What are the differences between continuous integration, continuous delivery, and continuous deployment?
Suggested answer: Developers practicing continuous integration merge their changes back to the main branch as often as possible. By doing so, you avoid the integration hell that usually happens when people wait for release day to merge their changes into the release branch.
Continuous delivery is an extension of continuous integration to make sure that you can release new changes to your customers quickly in a sustainable way. This means that on top of having automated your testing, you’ve also automated your release process and can deploy your application at any time by clicking a button.
Continuous deployment goes one step further than continuous delivery. With this practice, any change that passes all stages of your production pipeline is released to your customers. There’s no human intervention, and only a failed test will prevent a new change from being deployed to production.
Q3: What does SOLID stand for? What are its principles?
Suggested answer: S.O.L.I.D is an acronym for the first five object-oriented design (OOD) principles by Robert C. Martin.
- S – Single-responsibility principle. A class should have one and only one reason to change, meaning that a class should have only one job.
- O – Open-closed principle. Objects or entities should be open for extension, but closed for modification.
- L – Liskov substitution principle. Let q(x) be a property provable about objects of x of type T. Then q(y) should be provable for objects y of type S where S is a subtype of T.
- I – Interface segregation principle. A client should never be forced to implement an interface that it doesn’t use or clients shouldn’t be forced to depend on methods they do not use.
- D – Dependency Inversion Principle. Entities must depend on abstractions, not on concretions. It states that the high level module must not depend on the low level module, but they should depend on abstractions.
Although senior software developer interview questions and answers like these can be effective for identifying a qualified candidate, the in-person interview process becomes extremely laborious.
And if the questions are posed through an online or take-home test, the answers will need to be graded — along with the context of the candidate’s answer, like use of specifics and articulation of technical points. This, again, consumes the time of senior engineers.
Woven’s technical assessments are designed for specific roles in computer engineering, different levels of seniority, and the balance of skills (such as debugging and technical communication) germane to each role.
Results are graded individually by senior engineers in our network. Two independent evaluations are combined in an assessment of the candidate, and recommendations are made. We’re always available to discuss and interpret results.
That means your software architect interview preparation can begin with candidates that are already screened for required technical skills and ready for in-person interviews with your senior engineers.
System design interview preparation
When it comes to system design interview preparation, you have options. Some hiring managers find it helpful to review A Collection of System Design Interview Questions PDF. You can also check out a system design book like System Design Interview: A Strategic Guide for a Successful Interview.
We even have tips for an effective interview process with specific, well-tested senior software engineer interview questions for software engineer technical interviews in all major categories:
- Ask about credentials, then about problem-solving
- Ask about problem-solving, then about problems your company faces
- Ask about coding languages and explain what’s used in the role you need to fill
- Ask about experience with projects and include projects like yours
Woven is here to support your system design interview preparation. The questions outlined in this article are designed to build upon our foundation of technical screening, testing, objective comparison, and individual assessment that reduces engineering time and increases the productivity of your interviews.
When you’re ready to see what Woven can add to your critical hiring process for the best-qualified, most competitive engineers, sign up for a free trial.