Why preparation matters
Technology due diligence is the part of a deal process where buyers take a close look at what's under the bonnet. If you're preparing for a sale or investment round, it's also the part where founders and management teams are most likely to be caught off guard.
Preparation matters. Not because you need to hide anything, but because buyers form strong impressions quickly. A disorganised data room signals a disorganised business. A team that can't answer basic questions about their own architecture creates doubt. And doubt costs money, sometimes killing deals entirely.
What buyers actually look at
Technology due diligence covers more ground than most sellers expect. The scope varies by deal size and sector, but buyers consistently examine the same core areas.
Architecture and infrastructure. Buyers want to understand how the system is built and whether it can support the business at scale. Is it cloud-native or hosted on legacy infrastructure? Is there a single point of failure? Are services appropriately separated, or is everything tangled together in a monolith that's painful to change?
Team structure and dependencies. Who actually keeps this running? Buyers look closely at key person risk. If the CTO or a single senior engineer were to leave, what breaks? Thin engineering teams, undocumented systems, and high individual dependency are common red flags.
Security posture. This has become a standard part of any DD process. Buyers want to know whether access controls are in place, how data is stored and protected, whether there's a history of incidents, and whether the business meets any relevant compliance standards. ISO 27001 and SOC 2 certifications carry weight. Their absence raises questions.
Deployment pipeline and development practices. How code gets from a developer's machine to production tells you a lot about operational maturity. Buyers look for version control, test coverage, automated deployment, and some form of release cadence. The absence of these isn't always a deal-breaker, but it informs how much remediation is needed post-close.
Technical debt. Buyers don't expect a clean slate. They expect honesty. The question isn't whether debt exists; it almost always does. The question is whether the team understands it, has quantified it, and has a plan to manage it. Sellers who wave away technical debt are less credible than those who can say: here's what we know, here's how it affects velocity, here's what we'd prioritise.
The data room
A well-prepared data room signals competence. It also speeds up the process, which is good for everyone. Here's what to have ready.
Organisation and team
- Engineering org chart, including contractors and outsourced functions
- Role descriptions for key technical staff
- Tenure and location of the engineering team
Architecture and systems
- System architecture diagrams (current state, not aspirational)
- Infrastructure overview, including cloud providers, hosting costs, and key dependencies
- Third-party integrations and API dependencies
- Data flow diagrams, particularly if the business handles personal or sensitive data
Development and delivery
- Release history for the past 12 months, showing cadence and volume
- Source code repository overview, including age of codebase and primary languages
- Test coverage summary
- CI/CD pipeline documentation
Security and compliance
- Security certifications (ISO 27001, SOC 2, Cyber Essentials, or equivalent)
- Penetration testing reports from the past two years
- Incident log, including any breaches, near-misses, and how they were handled
- Data protection policies and GDPR compliance documentation
Licences and contracts
- Software licence inventory, including open-source dependencies and any copyleft licences
- Vendor contracts for key infrastructure and SaaS tools
- IP ownership confirmation, particularly for code written by contractors
Financials relevant to tech
- Engineering headcount costs
- Infrastructure and tooling spend
- Known remediation costs or planned investment
You don't need all of this polished to perfection. You do need to know where everything is and be able to provide it promptly when asked.
Common mistakes sellers make
The mistakes that create the most damage in a DD process tend to fall into a few patterns.
Over-polishing the narrative. Buyers who specialise in technology DD have seen a lot of data rooms. They know what a healthy system looks like and what a struggling one looks like. Attempts to dress up a difficult codebase with architectural diagrams that don't reflect reality are almost always spotted. The better approach is to present honestly and show that the team understands the limitations.
Hiding known issues. If there's a security vulnerability that's been in the backlog for 18 months, or a customer-facing system that's held together with workarounds, the buyer will likely find it. What they won't forgive is finding out you knew and said nothing. Transparency about known issues, paired with a credible remediation plan, is far better than the alternative.
No documentation ready. "We'll get that together" is a phrase that slows deals down and erodes confidence. The data room should be substantially ready before the process begins. If your architecture exists only in the heads of three engineers, that's a problem to fix before you go to market, not during.
Underestimating the timeline. DD is not a quick process. Buyers will ask follow-up questions. Your team will need to respond while still running the business. Deals with compressed timelines create pressure that leads to mistakes. Build in time.
Letting the CTO carry it alone. Technology DD touches legal, finance, HR, and operations. It's a business exercise with a technical focus, not a pure engineering exercise. Make sure the right people across the business are briefed and available.
How long to prepare
For most businesses, four to eight weeks of focused preparation is the right range. Less than four weeks and you're likely rushing; more than eight and you're probably over-engineering it.
The preparation time depends on how mature your documentation already is. If you have system diagrams, a maintained licence inventory, and a clean incident log, you're mostly pulling things together. If none of that exists, you're building from scratch, and that takes longer.
A useful starting point is to commission a lightweight internal audit before the formal process begins. This tells you where the gaps are and gives you time to address them without the pressure of an active buyer on the other side.
If you know a process is likely in the next 12 to 18 months, start preparing now. The businesses that come into DD looking ready are the ones that close deals at the price they were hoping for.
How TechDD can help
TechDD works with both buyers and sellers across PE and VC transactions. If you're preparing for a sale or investment round and want an independent view of how your technology will be assessed, we can help.
We offer sell-side preparation reviews that identify gaps before a buyer does, so you can walk into the process with confidence.
Get in touch to discuss your situation.
FAQ
What is sell-side technology due diligence?
Sell-side technology due diligence is a review carried out on behalf of, or in preparation for, a company that is about to be acquired or seek investment. The goal is to identify technology risks and weaknesses before a buyer does, so they can be addressed or clearly disclosed ahead of the formal process.
How long does technology due diligence take?
The buyer's DD process typically runs for three to six weeks, depending on deal complexity and the size of the technology estate. Preparation before the process begins usually takes four to eight weeks for most businesses.
Who leads the technology due diligence process?
On the buy side, DD is usually led by a specialist technology advisory firm or the investor's in-house technical team. On the sell side, preparation is typically led by the CTO with support from legal and finance. Some sellers appoint an independent adviser to run the preparation process.
What happens if issues are found during technology due diligence?
Issues found during DD can affect deal valuation, deal structure, or in some cases the decision to proceed. Minor issues are often priced into the deal or addressed through warranty and indemnity provisions. Significant issues, particularly those that were not disclosed, can cause a deal to collapse or result in meaningful price reductions.
Do I need to fix all technical debt before a sale?
No. Buyers expect technical debt to exist. What matters is that you understand it, have a realistic view of the cost to address it, and can demonstrate that it's managed rather than ignored. A credible debt register with a remediation plan is far better received than a claim that no debt exists.