How to Prepare Your Codebase for Technical Due Diligence

Investors and acquirers now routinely send a technical reviewer to look at your code before they close a deal. Most founders discover this too late — after they have committed to a timeline — and end up scrambling to clean up years of accumulated shortcuts in a matter of weeks. Getting ahead of this process is not about hiding problems; it is about presenting your codebase in a way that surfaces honest risks alongside honest strengths.

This guide walks through the specific steps to prepare your codebase for technical due diligence, whether you are heading into a Series A, a strategic acquisition, or a secondary transaction.

What Technical Due Diligence Actually Covers

Before you prepare, you need to know what reviewers look for. A standard technical due diligence engagement covers:

• Architecture and system design — Is the system decomposed sensibly? Are there obvious single points of failure?
• Code quality and maintainability — Is the code readable, tested, and consistently structured?
• Technical debt — How much of the team's capacity is consumed by maintenance and firefighting?
• Security posture — Are there known vulnerabilities, exposed secrets, or missing controls?
• Infrastructure and deployment — How does the team ship? Is there CI/CD? Is infra defined as code?
• IP and licensing — Do you own your code? Are open-source licenses compatible with commercial use?
• Team capability — Can the existing team execute the post-deal roadmap without key-person risk?

Reviewers are not expecting perfection. They are assessing whether the risks are known, manageable, and priced into the deal correctly.

Step 1: Audit Your Repository Before Anyone Else Does

Run your own internal audit first. The goal is to identify and document issues before a third party finds them without context.

Start with automated scans:

• Run a static analysis tool (ESLint, SonarQube, Semgrep, or equivalents for your stack) and export the report.
• Run a dependency vulnerability scan (npm audit, snyk test, pip-audit, or similar).
• Scan for accidentally committed secrets using a tool like truffleHog or gitleaks.

For each category of finding, write a short paragraph explaining what it is, why it exists, and what the remediation plan looks like. This narrative turns raw scan output into evidence of a mature engineering team, not evidence of a negligent one.

Prioritize Critical and High Findings

You cannot fix everything before a review. Prioritize:

1. Any exposed credentials or secrets in version control history — rotate these immediately.
2. Critical and high-severity dependency vulnerabilities with known exploits.
3. Authentication or authorization logic that has never been reviewed externally.

Leave medium and low findings documented with planned remediation dates. Reviewers respect triage; they distrust pretense.

Step 2: Document What the Code Does

Missing or outdated documentation is one of the most consistent red flags reviewers note. You do not need a wiki for everything — you need clarity on the critical paths.

Write or update the following:

• A README.md in every service or repository that explains what the service does, how to run it locally, and how to deploy it.
• An architecture diagram showing how your services communicate, what databases they use, and what third-party integrations exist.
• A data flow diagram if you handle personally identifiable information (PII) or payment data.
• A runbook for your most common operational tasks (deployments, rollbacks, database migrations).

If your architecture has evolved significantly, document the current state — not the aspirational future state.

Step 3: Make Technical Debt Visible and Bounded

Reviewers will find your technical debt. The question is whether they find it as a surprise or as a managed known quantity.

Create a simple technical debt register. A spreadsheet or a set of tagged GitHub issues works fine. For each item note:

• What the debt is (e.g., "authentication service does not support MFA")
• Why it was incurred (speed, team size, early pivot)
• What the estimated effort to remediate is
• Whether it blocks any post-deal initiative

A bounded, documented debt register signals a team that makes deliberate engineering decisions. An unbounded, undocumented mess signals a team that has lost control of its own codebase.

Step 4: Clean Up Repository Hygiene

Simple hygiene issues can unfairly color a reviewer's first impression. Before the review:

• Remove unused branches (or at least trunk-protect the main branch).
• Ensure commit history is meaningful — not a wall of "fix" and "wip" messages.
• Confirm that your CI pipeline passes cleanly on the main branch.
• Remove any commented-out code blocks that are more than a few weeks old.
• Check that environment-specific configuration is stored outside the codebase (environment variables, secrets manager — not .env files checked in).

Step 5: Prepare for the Team Assessment

Technical due diligence almost always includes conversations with engineering leads, not just a code review. Prepare your team to speak clearly about:

• Why certain architectural decisions were made and what the trade-offs are.
• What the on-call and incident response process looks like.
• How new engineers get up to speed (onboarding documentation matters here).
• What the deployment frequency and rollback process are.

Coaches do not help here. Reviewers can tell when an engineer is reciting a prepared script versus speaking from direct experience.

How Clixo Can Help

Clixo runs independent technical due diligence assessments for investors and pre-DD readiness reviews for founders. Both engagements follow a structured methodology covering code quality, architecture, security, and team capability — with a plain-language report that is useful for deal teams and engineering leads alike.

If you are preparing for a round or an acquisition and want an honest read before the formal process starts, reach out to start a conversation.