Acquiring a SaaS business can be a transformative move — but the real value (and the real risk) often lies under the hood. A polished product demo and strong revenue metrics can mask serious architectural problems that only surface after the deal closes. By that point, fixing them is expensive, disruptive, and entirely your problem.

This guide walks through the key dimensions of SaaS architecture evaluation every acquirer should cover before signing.

Why SaaS Architecture Matters in M&A

Unlike physical assets, software doesn’t depreciate visibly. A codebase riddled with technical debt, a fragile monolith, or a system with no disaster recovery plan won’t show up on a balance sheet — but it will show up in your post-acquisition roadmap, integration costs, and engineering team’s morale.

A proper technology due diligence process surfaces these risks before they become your risks.

1. Scalability: Can It Grow With You?

The first question to ask is whether the architecture can scale to support your growth plans. Key indicators include:

• Multi-tenancy model — does the platform properly isolate customer data, or does every client run on a separate instance (which is costly to manage at scale)?
• Horizontal vs. vertical scaling — cloud-native architectures designed to scale out are far more resilient than systems that can only scale up by upgrading hardware.
• Database design — look for signs of poor indexing, lack of query optimisation, or a monolithic database that will become a bottleneck at scale.

A system that works fine at 200 customers may buckle at 2,000. Due diligence should stress-test these assumptions, not take them on faith.

2. Technical Debt: What Are You Really Buying?

Every codebase carries some technical debt — the question is how much, and how manageable it is. Red flags include:

• Outdated frameworks or dependencies no longer receiving security patches
• Lack of automated testing (low code coverage leaves you flying blind during changes)
• Poorly documented or undocumented code
• Large volumes of duplicated logic spread across the codebase

Technical debt isn’t necessarily a dealbreaker, but it must be quantified. It directly affects how much it will cost to maintain, integrate, or extend the product post-acquisition.

3. Security & Compliance

For SaaS platforms — particularly those handling sensitive data — security posture is non-negotiable. Key areas to assess:

• Authentication & authorisation — are role-based access controls properly implemented? Is MFA supported?
• Data encryption — is data encrypted both in transit and at rest?
• Compliance — does the platform meet relevant standards (GDPR, SOC 2, ISO 27001, HIPAA depending on the sector)?
• Vulnerability history — have there been past breaches or security incidents? How were they handled?

Gaps here can translate into regulatory fines, customer churn, and reputational damage — all post-close.

4. Infrastructure & Resilience

How is the platform hosted and operated? Things to examine:

• Cloud provider and architecture — is it a well-structured cloud deployment, or a lift-and-shift of legacy on-premise infrastructure?
• Disaster recovery & backups — are backups automated and regularly tested? What is the recovery time objective (RTO)?
• Monitoring & alerting — does the team have visibility into system health, or are they relying on customers to report issues?
• Deployment pipeline — is there a CI/CD pipeline in place, or are deployments manual and error-prone?

A lack of operational maturity here significantly increases integration risk and ongoing operational cost.

5. Engineering Team & Processes

Architecture doesn’t exist in isolation — it reflects the team that built and maintains it. Assess:

• Bus factor — is critical knowledge concentrated in one or two individuals who could leave post-acquisition?
• Development practices — are there code reviews, branching strategies, and sprint processes in place?
• Documentation — is there sufficient technical documentation to onboard new engineers?

A strong architecture maintained by a well-organised team is a very different acquisition than the same architecture held together by two overworked developers with no documentation.

Don’t Rely on Self-Reported Information

One of the most common mistakes acquirers make is accepting the target’s own technical summary at face value. Founders are naturally optimistic about their product, and even well-intentioned descriptions can gloss over significant issues.

Independent, expert-led technology due diligence — with direct access to the codebase, infrastructure, and team — is the only reliable way to get an accurate picture.

How VeryDiligent Can Help

At VeryDiligent, we specialise in technology due diligence for M&A transactions. Our team of experienced engineers and architects conducts deep, independent assessments of SaaS platforms — covering architecture, code quality, security, infrastructure, and engineering practices — so you can make confident investment decisions.

Whether you’re a private equity firm, a venture capital investor, or a strategic acquirer, we give you the technical clarity you need before you commit.

Contact us today to discuss your upcoming transaction.

Related reading: The Guide to Technology Due Diligence for Private Equity Investors | What Should a Technology Due Diligence Report Include?