Best Technical Due Diligence Tools for M&A (2026)

For technical due diligence, no single tool wins: buy an audit service (Black Duck, SIG) when the deal needs a third-party report, use CAST Highlight for portfolios, CodeScene or SonarQube for maintainability, Snyk for known vulnerabilities, and repowise for a fast, evidence-backed read of one unfamiliar codebase. Each answers a different question, so match the tool to the question your investment committee is asking.

Vendor facts are from each vendor's own pages, read on 1 November 2026. Pricing is omitted because most of these tools sell by quote.

How we evaluated

Technical due diligence asks four questions, and we scored each tool by which of them it answers:

• Legal: which open source licenses are in the code, and does anything obligate the buyer?
• Quality: how costly is this code to change, and where is the debt concentrated?
• Security: what known vulnerabilities and leaked secrets exist today?
• People: who knows the code, and what happens if they leave?

We also weighed whether the tool can run on a target's code under an NDA, which means self-hosted or offline for many deals. For the step-by-step review itself, use the code audit checklist for technical due diligence; this post is only the tools view.

Black Duck audit services

Black Duck sells audits, not only a scanner. Its audits cover open source license obligations and conflict analysis, application security and code quality, and Black Duck says its audits have been a standard for software due diligence for 20+ years (as of November 2026, per blackduck.com). The output is a software bill of materials plus expert analysis.

Pick it if the deal turns on license and IP exposure and you want a named third party to sign the report. It is a service, so expect scheduling and a quote, not a command you run tonight.

SIG

SIG offers one-off scans and an ongoing platform, benchmarked against a large reference set. Per its own site, as of November 2026, its standards come from a quality model refined over 25+ years and are benchmarked against more than 40,000 systems. A Product Risk and Value Scan covers one product at a fixed price, and a Technical Debt Scan covers up to five systems (softwareimprovementgroup.com). Sigrid is the continuous portfolio product.

Pick it if you want a maintainability rating that an investor will recognise, backed by a firm that does this for a living.

CAST Highlight

CAST Highlight is a portfolio tool: it rates many applications at once. As of November 2026, CAST lists portfolio views of application health and tech debt, cloud readiness and open source risk, and links a technical due diligence resource (castsoftware.com). It offers a 14-day trial.

Pick it if you are acquiring a company with dozens of applications and need to rank them, not read one in depth.

CodeScene

CodeScene's Code Health is the closest public analogue to a per-file due diligence score. It aggregates 25+ factors into a 1 to 10 scale and marks files green, yellow or red, with hotspot and worst-performer KPIs across 30+ languages (as of November 2026, per codescene.com). The page does not describe an M&A workflow, so treat it as a measurement tool you apply yourself.

Pick it if you want a behavioural-code-analysis view with hotspots and a vendor-supported score. The comparison of what each score measures is in technical debt measurement tools compared.

SonarQube Server

SonarQube turns rule violations into a time estimate and a letter. Technical debt is the sum of remediation effort for all maintainability issues. The maintainability rating is that debt divided by estimated development cost (30 minutes per line by default): A is 0 to 5%, B to 10%, C to 20%, D to 50%, E above (SonarSource docs, November 2026).

Pick it if the target already runs Sonar, since you can read their existing history. Its debt number is a rule-count estimate, so do not read it as a price tag for a rewrite.

Snyk

Snyk covers the security slice. Snyk Code is static analysis that runs in the IDE and on pull requests, and Snyk Open Source targets vulnerable dependencies (as of November 2026, per snyk.io). We could not confirm license-compliance or SBOM features on that page, so check them with the vendor before relying on them in a deal.

Pick it if the diligence concern is known vulnerabilities in code and dependencies today.

repowise

repowise builds a local index of a repository and answers the quality and people questions from the code and its git history. It scores each file from 1.0 to 10.0 using 59 deterministic detectors with zero LLM calls, and it computes hotspots, owners, bus factor and fading ownership from git blame and history. A security pass scans for secret patterns, including in git history. It parses 28 languages to an AST and never edits your code.

uv tool install repowise
repowise init --yes --no-prose
repowise serve

--no-prose needs no API key and no network, so it can run on a target's code inside your own perimeter. Bug-fix history is traced to files, which shows the files that keep breaking. On-prem, air-gapped deployment, SSO and audit are in the enterprise offering, and repowise is AGPL-3.0 with a commercial license.

Pick repowise if you want the first read of an unfamiliar codebase in an afternoon, or you want an agent such as Claude Code to answer questions about it through MCP. The hosted and enterprise offerings add CVE triage, SBOM and VEX reporting and compliance reports.

How to choose

• Deal needs a signed report: Black Duck for license and IP, SIG for maintainability.
• Many applications to rank: CAST Highlight.
• One codebase, your own screening: repowise or CodeScene, then a manual review from the checklist.
• Security-first concern: Snyk, with a secret scan of git history.
• Target already uses SonarQube: ask for their dashboard and history first.

Individual advisors can start with the free OSS CLI. Funds and acquirers running many targets should plan for the enterprise, self-hosted setup.