During a recent due diligence engagement, a PE firm asked us to evaluate a “world-class engineering team” at a Series B SaaS company. The founders had impressive credentials—former Google and Facebook engineers with strong GitHub profiles. The product worked smoothly, customers were happy, and revenue was growing 200% year-over-year.

Then we asked to see their code review process.

What we discovered told a different story. Code reviews were perfunctory at best—rubber stamps rather than quality gates. Critical business logic lacked documentation. Database queries were inefficient. Error handling was inconsistent. Most concerning: the codebase showed clear signs of rapid growth without architectural discipline.

Our assessment: this was a team optimized for speed, not sustainability. While they’d successfully built a working product, they’d accumulated massive technical debt that would cripple future development.

The PE firm adjusted their valuation by $10 million to account for the inevitable engineering overhaul required.

Why Code Reviews Matter for Investors

Most investors focus on product features and user metrics, but technical founders evaluate the foundation beneath those outcomes. Code reviews reveal the engineering discipline that determines whether a platform can scale or will collapse under its own growth.

Here’s what we look for:

  1. Review Velocity vs. Thoroughness

Fast code reviews suggest either simple changes or insufficient scrutiny. We examine the balance: are reviews thorough enough to catch real issues, or are they just procedural checkboxes?

Red flag: Average review time under 10 minutes for substantial changes. Green flag: Evidence of back-and-forth discussions about implementation approaches.

  1. Documentation Standards

Good code reviews enforce documentation requirements. We look for:

  • Clear commit messages explaining the “why,” not just the “what”
  • Inline comments for complex business logic
  • Architecture decision records for significant changes

Red flag: Generic commit messages like “fixed bug” or “updated feature.” Green flag: Detailed explanations connecting code changes to business requirements.

  1. Testing Requirements

Professional teams require tests before merging code. We examine:

  • Test coverage requirements and enforcement
  • Types of tests (unit, integration, end-to-end)
  • Test quality, not just quantity

Red flag: Tests that simply verify code works, rather than ensuring it handles edge cases. Green flag: Tests that document expected behavior and catch regression errors.

  1. Security and Performance Awareness

Mature teams review code for security vulnerabilities and performance implications. We look for evidence of:

  • SQL injection prevention
  • Authentication and authorization checks
  • Database query optimization
  • Memory leak prevention

The Technical Debt Tell

The most revealing aspect isn’t what gets reviewed—it’s what gets approved despite obvious problems. Teams under pressure often accumulate technical debt by accepting “quick fixes” that create future maintenance burdens.

We’ve seen companies where code reviews became performative rather than protective. Everyone follows the process, but no one asks hard questions about architectural decisions or long-term maintainability.

What This Means for Valuation

Companies with rigorous code review practices typically have:

  • Lower bug rates in production
  • Faster feature development velocity over time
  • Easier integration of new team members
  • More predictable technical roadmaps

Companies with weak review processes face:

  • Increasing development costs as complexity grows
  • Higher risk of security vulnerabilities
  • Difficulty scaling the engineering team
  • Potential need for complete platform rewrites

The Builder’s Advantage

As engineers, we can distinguish between teams that write code and teams that build systems. We understand the difference between shortcuts that save time and shortcuts that create problems.

Most importantly, we know how to have these conversations with technical teams. We’re not auditors asking for documentation—we’re builders discussing craft with other builders.

The SaaS company we evaluated? They had to pause all new feature development to address their technical debt. Their competitor, with more disciplined engineering practices, gained significant market share during that period.

Code reviews might seem like an internal engineering concern, but they’re actually a window into the engineering discipline that determines scalability, security, and long-term viability.

Because in the end, sustainable growth requires sustainable code.