The Independent Guide to Technology Due Diligence

What TDD is, what it covers, and how to prepare for it. Written for founders whose companies are about to go through it, and for investors instructing it on a target.

Technical code review process

What is Technology Due Diligence?

A structured assessment of technical capability, risk, and opportunity

Technology due diligence (TDD) is an independent assessment of a company’s technology — its architecture, code, infrastructure, security, engineering team, and intellectual property — set against what the business plans to do with them.

Audits test compliance against a fixed standard. TDD tests whether the technology will support the business plan, what it will cost to run, and where the risks sit.

When TDD happens

Four situations usually trigger it:

  • Fundraising — investors at Series A and beyond routinely require an independent technical assessment before committing capital.
  • Acquisition — the buyer needs to know what they are buying, what it will cost to run, and what liabilities sit in the codebase.
  • Self-initiated healthcheck — the board or CEO commissions TDD to surface problems before an external party finds them.
  • Portfolio monitoring — PE firms run periodic TDD on portfolio companies to track technology health over time.

Who conducts TDD

TDD is carried out by independent firms staffed with former CTOs, engineering leaders, and architects — people who have built and run production systems. The work is as much commercial as technical; the code review is only useful insofar as it is translated into business consequence.

A good provider has no commercial relationship with the target or its vendors, bases findings on evidence rather than testimony, and reports what it finds without flattery.

Founder presenting to stakeholders

For Founders & CEOs

What to expect when your technology is under the microscope

A competent assessor does not expect a clean codebase. What they look for is honesty, a clear direction of travel, and evidence that you understand your own weaknesses.

Why TDD is happening to you

Someone with money on the line wants to understand what they are buying or backing. The usual triggers:

  • A funding round — investors want confidence that the technology can deliver the growth the plan promises.
  • An acquisition — the buyer needs to price technical risk and estimate integration cost.
  • A board-initiated review — someone on the board has been bitten before, or the business is outgrowing ad-hoc engineering practice.

How to prepare

Start six months out, if you can. The fundamentals:

  • Document your architecture. A current, accurate architecture diagram is the single most useful artefact you can hand over. If the assessor has to reverse-engineer the system from the code, that is itself a finding.
  • Know your technical debt. Every codebase has debt. The question is whether you know where it is, what it costs you, and what your plan is. “We have no technical debt” is a red flag, not a reassurance.
  • Put your IP house in order. Check that every employee and contractor has signed an IP assignment agreement. Review open-source dependencies for licence compliance. If any part of the system was built by a contractor who has since moved on, confirm that you own it.
  • Brief your CTO (or technical lead). They will be interviewed at length, and should be ready to discuss architecture decisions, trade-offs, and known risks without defensiveness.
  • Get the security basics in place. MFA on every production system, secrets management held outside chat and source control, and a documented incident response plan. An assessor will notice their absence.

What assessors look for

Assessors are pattern-matching against hundreds of previous engagements. The questions they are really asking:

  • Fitness for purpose — does the technology actually do what the business says it does?
  • Scalability — can it handle 10x the current load without a rewrite?
  • Resilience — what happens when things go wrong? Is there a single server, a single person, or a single undocumented process on which everything depends?
  • Velocity — can the team ship reliably, or does each release carry avoidable risk?
  • Awareness — does the team know what they do not know?

Common red flags

The findings that consistently raise concern:

  • Key-person dependency — one engineer holds the knowledge of a critical system, with no documentation and no succession plan.
  • No testing — minimal or no automated tests, where “testing” means someone clicks through the app before release.
  • Undocumented architecture — no diagrams, no runbooks, no record of why decisions were made.
  • Security theatre — policies that exist on paper but are not enforced in practice.
  • IP uncertainty — unclear ownership of code, especially code written by contractors or during previous employment.

The timeline

A typical engagement runs about four weeks. Roughly:

  • Week 1 — scoping, planning, and document requests.
  • Week 2 — document review and information gathering.
  • Weeks 3–4 — technical interviews, code and infrastructure review, analysis.
  • End of week 4 — report delivered, followed by clarification calls as needed.

The process is less disruptive than most founders expect. A well-prepared company gets through it without material impact on delivery.

Analysing investment data

For Investors & Acquirers

Making informed decisions about technical assets and risk

Technology due diligence answers a commercial question with technical evidence: is this technology worth what we are about to pay for it?

A good engagement produces a short, ranked assessment of technical risks and opportunities, with each finding expressed in commercial terms — what it costs to fix, how long it takes, and whether it affects the investment thesis.

Why TDD matters for deals

In most modern businesses the technology is a material part of what the buyer is acquiring and, often, a material part of the risk. That is true even where the business does not describe itself as a technology company.

TDD directly informs:

  • Pricing — technical debt, security exposure, and architectural limits translate into costs that a buyer can reflect in valuation.
  • Deal structure — material findings may warrant earnout conditions, escrow provisions, or specific reps and warranties.
  • Integration planning — understanding the target’s architecture before completion removes most of the expensive surprises.
  • Value creation — identifying opportunities for consolidation, simplification, or acceleration in the post-deal roadmap.

What a good TDD covers

Specifics vary by deal context, but the core areas are consistent:

  • Architecture fitness — is the system designed to support the business at its current and projected scale?
  • Code quality and technical debt — what is the maintenance burden, and is it growing or shrinking?
  • Security posture — what is the actual exposure, as distinct from what the policies claim?
  • Infrastructure maturity — is the platform reliable, observable, and recoverable?
  • Team capability — can the team double in eighteen months without losing the people who matter, and does the engineering organisation have the shape to absorb that growth?
  • IP and licensing — is ownership clean, and are there any open-source or third-party licensing risks?

TDD for growth theses

Most TDD framing is defensive — what is broken, what is risky, what will cost money to fix. For a growth-oriented acquirer the more useful questions concern capacity and leverage: what will the platform do that it does not do today, how quickly, and with what investment?

A growth-focused assessment should cover:

  • Scale ceiling — where the next bottleneck sits, at what revenue or user volume it begins to bite, and what the shape of the work is to move it. “Ten times today’s load” is the rough test; the sharper question is which failure mode appears first.
  • Engineering throughput under expansion — current velocity is a snapshot. What does it look like after eighteen months of aggressive hiring? Throughput rarely scales linearly with headcount, and the answer depends on architecture, tooling, and the maturity of engineering management.
  • Hiring and retention — can the target hire into a competitive market, and will the people who matter stay after the ownership change?
  • Platform extensibility — the cost of supporting a new geography, a new vertical, a white-label customer, or a multi-tenant deployment. Growth theses often rest on entry into adjacent markets; TDD can test whether the platform is shaped to support them.
  • AI and data posture — whether the data the business holds is structured, clean, and accessible enough to support AI features, and whether the engineering organisation has the skills to ship them.
  • Defensibility — the extent to which technology contributes to the competitive moat, via data network effects, integrations, workflow lock-in, or switching cost. Commercial DD asks whether the moat exists; TDD tests whether the technology supports it.

Growth-focused findings are forward-looking and investment-oriented. They describe what needs to happen, not only what has gone wrong.

Red flags that should concern you

Patterns that typically indicate deeper problems:

  • Technical debt that displaces new capability on the roadmap — a team that spends more time firefighting than building is a team whose output will not scale with headcount, and the gap widens with growth.
  • Opacity from the target — attempts to minimise, obscure, or delay access to technical information are themselves a finding.
  • Single points of failure — a lone server, a lone engineer, or a lone undocumented process. Concentration risk in technology is as material as concentration risk in revenue.
  • Release processes that require a code freeze, a dedicated rota, and a rehearsal for each deployment — the platform is not ready for the cadence a growth thesis will demand.
  • IP gaps — missing assignment agreements, undocumented contractor contributions, or unlicensed open-source components create material post-completion liabilities.

How TDD informs valuation

Findings translate into financial impact. A well-structured report provides:

  • Remediation costs — investment required to address identified risks, broken into immediate (pre-completion), short-term (first 100 days), and medium-term (first year).
  • Risk scoring — each finding categorised by severity (critical, high, medium, low) and likelihood of impact.
  • Benchmarking — how the target’s technology maturity compares with similar companies at the same stage.
  • Value creation opportunities — where targeted investment (platform work, key hires, a retired subsystem, a data or AI capability) would compound the growth case.

What the TDD firm will need from you

To produce a useful report the assessor needs the commercial context, not only the technical one:

  • The investment thesis in plain language, including the specific commercial claims that rest on the technology.
  • The management presentation and any model assumptions that are technology-sensitive — user scale, transaction volume, unit cost, roadmap dependencies.
  • Data room access, with guidance on which documents are authoritative and which are draft.
  • An introduction to the target’s CTO or technical lead, and an agreed process for interview scheduling.
  • Clarity on what the report will be used for — price negotiation, SPA structuring, integration planning, or all three.

Without this the assessor is guessing at what matters, and the output reads like a generic technical audit rather than a bespoke commercial assessment.

How TDD fits with commercial, financial, and legal DD

Technology touches each of the other workstreams. A coordinated approach avoids duplicated effort and closes the gaps that open between them:

  • Commercial DD assesses the market and the product’s fit for it; TDD assesses whether the technology will deliver the product as the market grows. The two share language around scalability, performance, and the customer experience.
  • Financial DD reviews R&D spend, capitalisation policy, and engineering cost base; TDD adds a view on whether the spend is productive and whether the debt trajectory is sustainable.
  • Legal DD reviews contracts, employment, and IP assignment on paper; TDD tests whether the facts on the ground match — whether contractor work has actually been assigned, whether open-source components comply with licence terms, whether data processing is consistent with stated contracts.

In practice the TDD firm should exchange findings with the other workstream leads at least twice during the engagement: early, to flag anything that reshapes scope elsewhere; and before the draft report, to reconcile anything that would otherwise appear twice with different framings.

Scope, cost, and what you receive

Engagement scope should match the deal. A sensible proportionality rule:

  • Bolt-ons and smaller deals — a two-to-three week red-flag engagement focused on the material risks and the quickly answerable commercial questions.
  • Mid-market deals — a four-week full engagement covering the eight assessment areas in appropriate depth, with findings ranked and costed.
  • Platform deals or unusually complex targets — six weeks or longer, with deeper code review, architecture workshops, and specialist streams where relevant (security, privacy, data).

Cost scales with scope and team seniority. Expect ranges, not list prices. A provider unable to explain the cost-to-scope trade-off clearly is unlikely to be the right choice.

The deliverable should include an executive summary that a time-pressed MD can read in ten minutes, a prioritised findings table with severity and indicative remediation cost, detail sections for each assessment area, a red / amber / green view mapped to those areas, and recommendations framed by urgency (pre-completion, first 100 days, first year). A narrative report without prioritised findings, or a findings list without commercial framing, is worth asking questions about.

Choosing a TDD provider

Quality varies widely. When selecting a provider, look for:

  • Independence — no commercial relationship with the target or any technology vendor.
  • Practitioner-led — assessments conducted by people who have built and run production systems, not junior analysts working through checklists.
  • Commercial awareness — findings expressed in business terms, not purely technical language.
  • Proportionality — scope and depth matched to deal size and risk profile.
  • Candour — uniformly positive findings should be treated with suspicion.

The TDD Process

What happens during a technology due diligence engagement

Engagements follow a structured sequence — documents first, then people, then systems — so that technical deep-dives are targeted rather than speculative.

A typical engagement runs about four weeks: one week of scoping and planning, one week of document gathering, two weeks of interviews and technical review, with the report delivered at the end of week four and follow-up calls as needed. Compressed timelines (auction processes, time-sensitive deals) can run in as little as two weeks at reduced depth. The critical path is almost always access to people, not access to documents.

1

Scoping

Define objectives, agree scope, issue document request list.

2

Document Review

Analyse architecture diagrams, policies, contracts, and org charts.

3

Technical Interviews

Interview CTO, engineering leads, and key technical staff.

4

Code & Infrastructure

Review code quality, CI/CD, cloud architecture, security posture.

5

Report

Deliver findings with risk scoring, remediation costs, and recommendations.

Key Assessment Areas

The eight dimensions of a thorough technology due diligence

Emphasis shifts with deal context, target maturity, and acquirer priorities, but the areas of investigation are broadly consistent. A thorough assessment covers all eight of the following, weighted by what matters in the specific situation.

Software Architecture

Modularity, design patterns, scalability approach, and fitness for purpose.

Code Quality & Technical Debt

Maintainability, test coverage, complexity metrics, and debt trajectory.

Security & Compliance

Vulnerability management, access controls, data protection, regulatory posture.

Infrastructure & DevOps

Cloud architecture, CI/CD maturity, monitoring, disaster recovery.

Scalability & Performance

Load handling, bottleneck identification, growth readiness.

Team & Organisation

Skills coverage, key-person risk, hiring pipeline, knowledge management.

Intellectual Property

Ownership chain, licensing compliance, open-source exposure.

Data & AI

Data assets, model governance, pipeline reliability, AI strategy.

About This Site

An independent educational resource on technology due diligence, maintained by practitioners in the field. Better-informed participants produce better outcomes — for founders, for investors, and for the companies they build together.

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