You've closed the round. Or you're close. An investor has asked for a technical due diligence review as part of the process, or you know it's coming in the next raise.
This is the moment founders discover what their codebase actually is.
What technical due diligence looks for.
A technical due diligence review isn't a code quality audit. It's an assessment of risk. The investor wants to know: is this system capable of delivering what the business is promising, and what would it cost to fix it if not?
The questions that come up:
- Is the architecture scalable, or will it need to be rebuilt before the company can grow?
- Are there security vulnerabilities that create liability?
- Is the codebase maintainable, can engineers other than the original builder work in it?
- Are there third-party dependencies that create concentration risk?
- Is there documentation? Test coverage? Deployment processes that don't rely on one person's laptop?
- Is the intellectual property clearly owned by the company, not a contractor or a third-party platform?
Most early-stage codebases have gaps in several of these areas. That's normal. What matters is whether the gaps are known, understood, and have a credible remediation plan.
The signals that raise flags.
Investors doing technical due diligence have seen enough codebases to know what healthy looks like. A few things that consistently raise flags:
- No version control history, or a history that shows one person doing everything
- No test coverage, or tests that clearly don't run
- Infrastructure that can't be reproduced from documentation. It only works because someone set it up manually and remembers the steps
- Third-party services embedded so deeply that replacing them would require a rewrite
- IP ownership that's ambiguous: code written by contractors without clear assignment clauses, or built on top of platforms with restrictive terms
- No monitoring or alerting. Nobody would know if the system went down at 3am
None of these are automatic deal-breakers. But each one is a conversation the founder needs to be prepared for, with an honest answer rather than a deflection.
The question founders should ask themselves now.
If an investor asked to see your codebase tomorrow, could you explain it?
Not the features. The architecture. Where the data lives. How the services connect. What happens when something fails. Who owns what. What it would take to double the current load.
If you can answer those questions confidently, you're probably in reasonable shape. If you're not sure, that's useful information worth knowing before you're sitting across from someone whose job is to find the gaps.
Getting ahead of it.
A pre-due diligence technical review is one of the highest-leverage activities a well-funded founder can do before the next raise. Not to make the codebase perfect, but to understand what's there, what the real risks are, and what has a credible remediation path versus what's a genuine liability.
Investors respect founders who know their system's limitations and have a plan for them. What creates problems is surprise: discovering something in due diligence that the founder clearly hadn't considered.
The best time to do this review is before you need it.