Karl Hughes

Karl Hughes

24 Startup CTO Interview Questions

24 Startup CTO Interview Questions

Hiring a Chief Technology Officer (CTO) is a difficult feat at the best of times. But for startups, a lot rides on choosing the right candidate. Whereas in a large organization a CTO might be expected to focus largely on high-level strategic decisions such as overseeing development teams and finding integration partners, in the startup environment, it’s all hands on deck — from day one.

Your CTO might have to do everything from hop into the code to establish lead sprint meetings, and find time to travel to tech conferences.

I was recently asked to help a startup interview a prospective CTO. Here are some of the questions I used during the interview process, and I hope they help you in your CTO hiring process. I’ve ordered these by topic so that you can jump to the ones that best suit your startup’s needs.

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MVP Development

For many startups, building a minimal viable product (MVP) is the first technical job to get done as soon as the logo’s been decided upon and the startup garage has been rented. And guess what? For many startups, building it isn’t going to get outsourced to Upwork. Use these questions to gauge your potential CTO’s readiness to get the job done.

1. Tell Us About Your Previous Experience?

You want to gauge whether your potential CTO has pulled off an MVP-development project before. Gambling on a first timer could be a risky proposition. How long did development take? What did the workflow look like? Don’t be shy about asking for the details to make sure that you’re dealing with somebody who will be comfortable taking on your project.

What to look for: Previous MVP experience with a specific completion timeline.

What to avoid: The obvious red flag is a potential CTO that has never gotten involved in the MVP creation process before and doesn’t know much about what it typically entails. Whether this will be a dealbreaker for you really depends upon your risk tolerance profile.

2. What’s Your Preferred Software Stack?

What tools is your potential CTO familiar with? If you’ve already decided upon a stack, perhaps based upon your other development resources, then you’ll want to look for somebody whose experience is congruous with your own. If your guys use Jenkins but the potential hire only knows Bamboo, this could be a problem.

What to look for: Somebody who knows the stack that you’re interested in.

What to avoid: It may make life very difficult if your potential hire has never worked with the tools you want to get onboard with. Again, whether this is acceptable or now will depend upon how much risk you’re comfortable taking on.

3. Tell Me About A Time You Joined An Existing Codebase That Was In Bad Shape? How did you get acclimated to it? How did you improve?

In Startupland, QA doesn’t always get the attention it deserves. There are sprint deadlines to meet and resources can be constrained at the best of times. Will your potential hire balk at the site of a code jungle or get to grips with it? Finding out what the potential hire did in order to turn around a situation that was less than ideal can also give you valuable insights about the potential hire’s problem management skills.

What to look for: Somebody who’s pulled off the process of getting to work on a codebase that was in less than ideal condition.

What to avoid: If you need somebody who’s going to be comfortable diving in the deep end, then you probably don’t want a candidate that would freak out at the first sign of trouble. If that’s the case, look for somebody who has experienced getting their hands dirty with an ugly codebase.

Note: If you’re looking for more reading material, I’ve assembled a list of my favorite books for startup founders here.


A startup CTO will often fulfill functions that budge into traditional HR territory. While human resource functions can be invaluable for their skills in keeping track of benefits and vacation leave, a coder is often the best-placed resource to hire another coder.

4. Tell me about the last hire you made. What was your process and who did you hire? Why did they stand out?

Here, you want to find out whether the potential CTO has a discerning eye for talent. The technical job market is incredibly competitive and it’s important that your potential CTO will be able to separate outstanding candidates from those who are only likely to make a mediocre contribution to your team.

What to look for: Can your potential CTO provide strong reasons for why they chose to make certain hiring decisions? What did they look for in the successful candidate? Do those reasons align with the type of talent you’re looking to onboard?

What to avoid: You’re probably not looking to hire somebody who can’t articulate why he/she made certain hiring decisions

5. Have you ever made a bad hire? When did you figure it out? What did you do?

A bad hire can spell disaster for an early stage startup that doesn’t have the financial resources to throw good money after bad. Here, you’re trying to assess how quickly your potential CTO remedied the situation — and whether they did at all.

What to look for: Somebody that quickly spotted that there was a problem and took swift action to bring the issue to the bad hire’s attention.

What to avoid: Response like “we were a chill company, we didn’t really care” definitely don’t communicate the right attitude. You’ll want somebody that didn’t let a bad situation persist and took action.

6. Have you ever had to let someone go? Why?

While the above will provide you with a good sense for the potential hire’s overall managerial ability, you’ll want to dive a little deeper in order to see whether the maybe-CTO was capable of following through on the uncomfortable act of terminating somebody’s employment.

What to look for: Somebody that was able to swifty do what was necessary for the company’s best interests.

What to avoid: Somebody that procrastinated over the job of firing somebody. There’s a chance that they might do the same if the issue crops up at your company.


These days cybersecurity is a concern for organizations both small and large. One of the key functionalities of a startup CTO is going to be around making sure that all internal systems are properly secured. Does the potential CTO have the required background in security to know what to look for?

CTO candidates should know a substantial amount about security

7. What are some of the first things you would check when evaluating organizational security at a startup?

The potential CTO’s in the door. Now what. Do they have a coherent plan for how to bring a security culture to an early stage startup? (Check out this post for tips on what to implement)

What to look for: Somebody that knows what to look for and is able to demonstrate a readiness for how to implement it.

What to avoid: Responses like “security isn’t a big focus on mine” or “it could probably wait” are likely indicative of a candidate that will be happy to put security on the backburner for as long as possible.

8. What are some common security issues you’ve seen in startup codebases in the past? What steps did you take to mitigate them?

Again, previous experience is telling. Has your potential CTO encountered common unsecure codebases in the past? And if so, what exactly did they do to take action?

What to look for: Experience securing codebases and stacks isn’t necessary, but it would certainly give a potential candidate a leg up. Somebody with experience actioning security best practices might deserve a leg up in your hiring process. A coherent approach to tackling these security issues also vouches for their project management skills.

What to avoid: Candidates who have never had to grapple with this issue before might not have the experience to contribute if they run into issues like this at your organization.

9. When do you not fix a security vulnerability?

This is something of a trick question. Cybersecurity measures have to be weighed against the resources of the company. For instance, rolling out company-wide encryption on all devices would not be appropriate for most startups. But for organizations that have to comply with data governance standards such as HIPAA, this might be a legislative need.

What to look for: Somebody that demonstrates that they would take a resource-sensitive and measured approach to implementing cybersecurity.

What to avoid: Somebody that has great security knowledge but fails to weigh up countervailing factors such as cost.

Project Management

CTOs can become mini project managers responsible for allocating resources in the development team as carefully as the company needs them to be allocated. Ask a series of questions designed to tease out just how good they might be at this important aspect of the job.

10. Describe for me an “Agile” development workflow you’ve used in the past?

If you’re a startup organization, then we reckon there’s, well, quite a high chance that you’re going to be using Agile as your formal development and project management methodology. As with most things, it’s generally advantageous if the CTO candidate can demonstrate that they have prior experience in this field so that they can hit the ground running.

What to look for: Somebody that, through recounting prior experience, can demonstrate that they have good mastery over the Agile process and can walk you through a prior workflow that they successfully implemented.

What to avoid: If your potential CTO has neither heard of Agile nor can tell you what a good workflow would look like, then they’re probably going to struggle in an Agile-first environment.

11. Describe for me an “Agile” development workflow you’ve used in the past?

This is a great and pointed question to ask if you’d like to learn more about how your potential CTO would handle prioritization and triaging feature requests. Having a clear head about what is necessary and what isn’t is a great way to discern how good your candidate is at prioritization.

What to look for: A candidate that is able to demonstrate a clear methodology for how to prioritize feature requests.


AWS has its Well Architected Framework and most services and infrastructure products have certain best practices that it is ideal for a candidate to be experienced with if they are going to be working with that stack.

A CTO must handle architecture

12. Describe the architecture of a web application you worked on recently.

You’re again looking for somebody whose experience mirrors as closely as possible the type of stack and products that you’re working on in your organization.

What to look for: Similarity between the architectures that the candidate has worked on and what you need.

What to avoid: Obvious dissonance between experience and your envisioned needs when it comes to stack.

13. What data storage systems have you used in the past (eg: MySQL, Mongo, Redis)? Which would you use again? Which would you not?

Besides mastering common industry tools, a good CTO should be able to provide constructive input to other stakeholders on the pros and cons of adopting certain technologies — whether that’s a database engine, a CMS, or an internal communications tool.

What to look for: Somebody able to clearly articulate preferences and back them up with strong reasoning. This person can become an influential internal stakeholder in your organization.

What to avoid: “I like everything I’ve worked with.”MySQL, NoSQL — it’s all the same to me.” These kinds of opinions might stymie key development decisions.

14. What software design patterns do you think are underrated?

Sure, you want somebody that knows their way around the most common tech stacks in your industry. But a touch of contrarian mightn’t go amiss either. Whatever personality type you think is going to gel best with your development team, it’s a good idea to sound out their opinions about software development. This one should be a sure-fire conversation starter.

What to look for: Somebody with insights into a software design pattern that they think is underrated.

What to avoid: Somebody who doesn’t have strong feelings about current trends in the industry and isn’t keeping up to date with emerging trends.

15. Have you made a rebuild vs. refactor decision on a major piece of software before? Walk me through the process and how you eventually solved it.

Deciding whether to rebuild or refactor software is an important development decision that can have important repercussions for the final product that you put out. Rebuilding results in a longer release cycle while refactoring will set back the time it takes for you to see initial results a little.

What to look for: Your potential CTO should be familiar with the various pros and cons of when to go with either approach.

What to avoid: If your potential CTO isn’t aware of when either decision might be more prudent, then this might be a worrisome sign.

Bug Triage

Knowing what bugs to prioritize and how to roll out an effective system for prioritizing fixes is an essential development skill.

16. Describe for me a recent bug you had to trace down. How did you do it? What tools did you use? Were you able to replicate it? Were you able to fix it?

What to look for: You’ll want to look for a potential candidate that demonstrates proficiency in diagnostics and identifying and logging system bugs. Ideally, you’ll also want to find somebody that is familiar with rolling out a formal bug tracking workflow.

What to avoid: Somebody who isn’t familiar with formal systems for logging and tracking bug resolution.


Debugging software and making sure that all the code that goes out the door is working as expected is also a vital part of the development process. You’ll want to make sure that your CTO candidate has good experience in this area of development too.

17. Do you use TDD? Do you think it’s important?

Test Driven Development (TDD) is an important methodology for QA-ing code — but not every software developer prefers it. Your CTO should have an opinion based on experience, but be pragmatic enough to work within your business’ time and financial constraints.

What to look for: Candidates should know the difference between traditional QA and TDD and be able to articulate a business case for both.

What to avoid: Candidates unfamiliar with TDD or QA best practices in general.


DevOps seems to be on everybody’s lips right now. By integrating development and operational teams, DevOps has made it easier than ever for software teams to quickly and continuously roll out product iterations.

CTOs must handle devops and server administration

18. What has your typical deployment pipeline looked like in the past? What did you like or dislike about it?

Your goal here could be to get a sense for the kind of workflows that your potential CTO is already familiar with. Their opinions can be used to assess what they think about these practices and how willing they’d be to adopt them in this role.

What to look for: Candidates should be aware of DevOps and be able to articulate the benefits of continuous integration and deployment (CI/CD). Opinions about what benefits it could bring could indicate the passion they’re likely to bring to the job if this is a key part of your approach.

What to avoid: Candidates should certainly be able to talk about the pros and cons of various deployment models, including DevOps.

19. How do you feel about containers? When is the right time to adopt a solution like Kubernetes?

Containerization is making waves in the software development industry and in theory, it makes it easier to run the same code in multiple environments. In practice, Kubernetes can overcomplicate simple applications, so it’s not right for every startup.

What to look for: A CTO candidate should be well-versed in containerization and what Kubernetes is bringing to the software world. They should also be able to offer reliable guidance on when a good time for adoption might be.

What to avoid: Candidates who have a fixed mindset about deployments or have not progressed past using virtual machines (VMs).

Data Science

Data science and machine learning are helping teams improve efficiency and realize new uses for information already sitting on their servers. Does your candidate know much about developments in this space?

20. Tell me about a data science or machine learning project you led in the past. What did you learn in the process?

What to look for: If your potential CTO has hands-on experience with an AI and ML project then this should be considered a big advantage. Did they pick up skills that you could exploit in this role?

What to avoid: Again, candidates that are not up to speed on this rapidly changing area of tech could be at a disadvantage.

Vendor and Customer Relations

A great CTO won’t only be sequestered in the development room browsing Reddit and downing coffee. They might also need to attend conferences, work with customers, and liaise with vendors and integrations partners. Does this potential CTO have the technical know-how to match their development prowess?

21. Have you ever managed a relationship with a software or hardware vendor in the past? Have you negotiated price discounts? Tell me about it.

What to look for: This is a perfect question to use to assess how comfortable the candidate is in a business rather than a development context. How did they handle the negotiation complex? They might hint that they prefer to be in office rather than out of it. If the potential CTO’s role could be heavily customer-facing, this could be a competitive disadvantage.

Team growth and retention

If you’re invested this much time in considering what your potential CTO could bring to the team, then you’ll probably want to keep them around for as long as possible. Moreover, will they keep an eye on retention among your development resources? This is a key attribute that could save your startup a lot of money. A revolving door is frustrating — not to mention expensive.

22. Tell me about your team management style. How would you describe it?

What’s your startup’s culture like and what type of management would you like the CTO to bring to the development function? This is another key question that you can use to assess cultural bias in addition to hard skills.

What to look for: A management style that is congruous with the overall culture of the company and which will mirror your own approach.

What to avoid: Any signs of micromanagement could be seen as a red flag. Additionally, you’ll possibly want to avoid hiring a candidate who has a very different way of managing resources than you’re accustomed to.

23. How often did you have one-on-ones with your direct reports? How about your reports’ reports?

Again, this question is a great way for gauging what kind of people skills the CTO could bring to the team. Has the CTO managed subordinates before or will they need to pick this up on the job.

What to look for: if you’re looking for somebody with experience managing subordinates, then, well, this is what you’ll need to be looking for.

What to avoid: If a candidate has never managed before, or has only ever assumed responsibility over interns, then they’re probably going to have to learn management on the fly.

24. What do you see as the key to retaining good employees?

Finally, the retention question. You can use this pointed question to learn a lot about how much importance your potential hire places on keeping a revolving door from spinning around.

What to look for: Somebody that places strong value on retention and would be proactive about avoiding it.

What to avoid: A candidate that doesn’t see retention as an issue and would invest minimal effort in preventing churn within the development department.

Further Reading

The Phoenix Project book cover

The Mythical Man-Month: If you want a little insight into what your CTO will be facing as they take on the role at your startup, this is one of my favorite books. You don’t have to be technical at all to see how software projects can go off the rails with the wrong leadership in place.

The Phoenix Project: This enjoyable piece of fiction also helps non-technical founders understand the dynamics of software project management. While your CTO will likely take on the role of leading these initiatives, you can be their backup if you know what direction they’re heading in.

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