What Questions to Ask a CTO During Due Diligence
The CTO interview is one of the most valuable — and most underutilised — elements of a technology due diligence. Done well, it surfaces insights that no code scanner or documentation review can replicate. Done poorly, it becomes a polite conversation that tells you very little about the real risks hiding in the platform.
The difference lies in the questions you ask.
Here is a framework for getting the most out of your CTO interview during due diligence — covering architecture, technical debt, security, team, and the questions that reveal how a technology leader really thinks.
Before You Start: Set the Right Context
The CTO interview should never happen in isolation. By the time you sit down with the technical lead, you should already have reviewed the available documentation, conducted your initial codebase and infrastructure analysis, and formed preliminary hypotheses about where the risks might lie.
The interview is not a fishing expedition — it is a targeted conversation designed to validate, challenge, and deepen your preliminary findings. Go in with specific questions informed by what you have already seen.
Architecture and Scalability
“Walk me through the architecture. What are you most proud of — and what would you rebuild if you could?”
This is one of the most revealing questions you can ask. The first half gives the CTO an opportunity to explain the platform; the second half tells you where they know the problems are. A technically honest CTO will have a clear answer. Evasiveness here is a yellow flag.
“What happens if your user base doubles in the next 12 months? Where does the system start to struggle?”
A strong CTO will answer this immediately and specifically. Vague reassurances about “horizontal scaling” without substance suggest either shallow technical understanding or an attempt to manage the conversation.
“How is multi-tenancy handled? What is the data isolation model between customers?”
For SaaS platforms in particular, this is non-negotiable. Weak tenant isolation creates security and compliance risk that is expensive to remediate post-close.
Technical Debt and Code Quality
“How would you characterise the level of technical debt in the codebase, and what is your plan for addressing it?”
Every honest CTO will acknowledge some level of technical debt. The concern is not its existence — it is whether the team has visibility into it and a credible plan for managing it. No plan, or defensive denial, is a significant red flag.
“What is your test coverage like, and how confident are you in your CI/CD pipeline?”
Low test coverage and manual deployments increase the risk and cost of every future development cycle. This question tests both technical maturity and the CTO’s willingness to be candid.
“Are there any components of the system that only one or two people truly understand?”
This cuts directly to key person risk — one of the most common and underestimated risks in technology acquisitions. Watch for hesitation or overly confident denials.
Security and Compliance
“What does your security posture look like? Do you hold any certifications, and when were you last assessed?”
SOC 2, ISO 27001, and Cyber Essentials are meaningful signals of security maturity. Absence of any certification — particularly in a platform handling sensitive data — warrants deeper scrutiny.
“Have you experienced any security incidents or data breaches? How were they handled?”
The answer matters less than the response. A CTO who gives a clear, composed account of an incident and what was learned is demonstrating exactly the kind of operational maturity you want. Defensiveness or vague reassurances are concerning.
“How do you manage third-party risk — vendors, open source libraries, and cloud providers?”
Modern platforms are only as secure as their weakest dependency. A strong answer will reference a defined process; a weak answer will be largely improvised.
Engineering Team and Organisation
“How is knowledge distributed across the team? What happens if your two most senior engineers leave tomorrow?”
Direct, specific, and difficult to deflect. The answer tells you immediately whether the organisation has addressed its bus factor — or is hoping you won’t ask.
“How do you onboard new engineers? How long before they are productive contributors?”
A long or difficult onboarding process is a signal of poor documentation, fragmented architecture, or both — all of which add post-acquisition integration cost.
“How has engineering team stability been over the past 12 to 18 months? Have you lost any key people?”
Retention data is more reliable than assertions about culture. High turnover in the 12 months before an acquisition is a pattern worth investigating.
The Questions That Reveal the Most
Beyond the technical specifics, two questions consistently produce the most revealing responses:
“If this acquisition goes ahead, what are the two or three things you would want the new owner to prioritise in the first six months?”
A CTO who answers this thoughtfully is telling you what they believe is most important — and often, what they are most worried about. It is an invitation to candour that many will take.
“What keeps you up at night from a technology perspective?”
Simple. Direct. Disarming. The answers are almost always more honest than anything that comes before.
Why Independent Assessment Still Matters
A well-conducted CTO interview is invaluable — but it is not a substitute for independent technical assessment. CTOs are advocates for their own platforms, even the most candid ones. They may not be aware of issues buried deep in the codebase, and they have an inherent interest in presenting the technology favourably.
The most reliable approach combines a structured CTO interview with independent code review, infrastructure assessment, and security analysis — so that what you are told can be validated against what the evidence actually shows.
At VeryDiligent, our discovery sessions with target engineering teams are a core part of every technology due diligence engagement — structured, specific, and informed by prior technical analysis to ensure you get answers that are genuinely useful.
Contact us today to discuss your upcoming transaction.
Related reading: How to Evaluate a SaaS Architecture Before Acquisition | Cybersecurity Due Diligence: The New Dealbreaker | Our Framework for Technology Due Diligence Explained