How Much Does Technical Due Diligence Cost?

What drives the price

Five inputs set the cost of a tech DD engagement. Scope breadth: code quality alone is cheapest; adding infrastructure, security posture, data practices, IP hygiene, and team assessment each add days. Codebase size and repository count matter, though less than buyers assume — a reviewer samples strategically rather than reading everything. System count matters more: three products on separate stacks is nearly three reviews.

Access level changes the work fundamentally: full repository and infrastructure access with engineer interviews supports real findings, while a review conducted through demos and management presentations is closer to informed guessing and should cost — and be trusted — accordingly. Finally, deadline compression carries a premium: diligence squeezed into deal timelines means senior reviewers rearranging their week. When I scope these, the first call establishes exactly these five variables, and a firm quote before that conversation is a guess.

The tiers: red-flag review versus full assessment

A red-flag review at $3K-$8K answers one question: is there anything here that should stop or reprice the deal? It covers a structured scan of the codebase for the classic hazards — secrets committed to repositories, license contamination, absent tests, no CI — a couple of hours of architecture interviews with the engineering lead, and a check of deployment and backup reality. It won't map every risk, but it reliably surfaces the catastrophic ones within a week.

A full assessment at $15K-$40K adds depth on each axis: code quality with concrete evidence, scalability analysis against the business plan, a security review beyond the surface, data and privacy compliance, engineering process maturity, and — often most valuable — key-person risk: how much of the system lives in one head. Deliverables should include a remediation cost estimate, because "the code is rough" only matters when translated into what fixing it will cost the buyer post-close.

What a good report contains — and the one number that matters

A useful tech DD report reads like an engineering document, not an opinion column. It maps the architecture as it actually exists, grades code quality with cited examples rather than adjectives, states what was reviewed and what wasn't, and ranks findings by severity with the evidence behind each. It covers security posture, operational maturity — can they deploy safely, do backups restore, what happens when the one person who knows the deploy process leaves — and the honesty of any technical claims made in the pitch.

The single most valuable output is the remediation estimate: what it will cost, in money and months, to bring the system to the standard the buyer's plans require. That number converts diligence findings into deal terms — price adjustments, escrow holdbacks, or post-close budget. In my experience a report without remediation costing leaves the hardest work undone, because someone still has to translate findings into decisions.

What cheap reviews miss

The failures I see in bargain diligence cluster in predictable places. License contamination: a copyleft-licensed dependency compiled into proprietary code can poison the IP a buyer thinks it's acquiring, and finding it requires an actual dependency audit, not a glance at the repo. Secrets in version history: credentials deleted from current code but living forever in git history. Bus factor: the demo works beautifully, and exactly one engineer — possibly one who won't stay post-acquisition — understands how.

Also commonly missed: infrastructure that exists only as manual steps in someone's memory, test suites that exist but assert nothing (coverage theater), and the gap between claimed and actual scale readiness — systems described as handling millions of users that have never seen ten thousand. None of these show up in a management presentation, which is precisely why diligence that never touches the repository and never interviews engineers under NDA misses them.

How to sanity-check a diligence quote

A credible quote specifies the artifacts to be reviewed — repositories, infrastructure configuration, dependency manifests, incident history — the number of interview hours with the target's engineers, the report format, and what's explicitly out of scope. Senior reviewers price at roughly $1K-$2.5K per day depending on market, so you can back into whether the quoted price buys real review time or a template with your logo on it.

Be cautious of two extremes: a suspiciously cheap fixed quote issued without a scoping call, which usually means a checklist pass that would miss everything in the previous section, and open-ended hourly engagements with no deliverable definition, which drift. Also confirm independence — the reviewer should have no stake in the deal closing and no prospect of post-close work they'd be tempted to sell. The report's value rests entirely on the reviewer having no reason to soften it.

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