02.27.26 by Steven Stites

SaaS providers that integrate directly with customer environments face a persistent challenge: delivering secure, reliable connectivity to customer data sources without introducing operational drag or security exposure. Historically, VPNs have been the default mechanism for accessing customer networks. While workable for small deployments, VPN-based architectures quickly become brittle as customer counts, endpoints, and data flows increase.

Network as a Service, or NaaS, represents a fundamentally different approach. Instead of extending private networks through point-to-point tunnels, NaaS creates a cloud-managed connectivity layer purpose-built for multi-tenant SaaS access at scale. This model eliminates many of the constraints that make VPNs difficult to operate in modern SaaS environments, particularly when customer connectivity is a core part of the product experience.

Understanding NaaS in the Context of SaaS Customer Access

Network as a Service is a cloud-native networking model that abstracts connectivity, security, and routing into a centrally managed platform. SaaS providers deploy lightweight software or virtual connectors inside customer environments that establish outbound, policy-controlled connections to a provider-managed control plane.

Rather than extending a corporate network into every customer site, NaaS enables application-specific connectivity that is isolated per customer, centrally governed, and designed to scale linearly as new customers are added. This approach aligns naturally with SaaS business models where rapid onboarding, predictable operations, and strong security boundaries are essential.

In practice, this model is best suited for connecting a SaaS provider’s cloud environment to customer-controlled networks and data—often across different organizations—not for extending connectivity within a single enterprise.

Why VPNs Break Down for SaaS at Scale

VPNs were designed for site-to-site connections, not for public cloud-hosted SaaS platforms that must securely connect to hundreds or thousands of independent on-prem customer environments. As SaaS adoption grows, VPN-based customer connectivity introduces several systemic limitations.

• Per-customer deployment delays: Each new customer requires manual VPN provisioning, coordination of credentials, firewall changes, and ongoing maintenance.

• Non-linear scalability: VPN gateways, concentrators, and routing tables become bottlenecks as endpoint counts increase from 10 to 100 to 1,000.

• High operational overhead: Certificate rotation, tunnel troubleshooting, firmware updates, and customer-specific configurations consume significant engineering time.

• Expanded attack surface: VPNs often provide broad network access, increasing blast radius if credentials are compromised.

These challenges compound as SaaS providers scale, directly impacting onboarding speed, reliability, and cost structure.

Deployment Speed: NaaS vs VPN Per Customer

One of the most immediate differences between NaaS and VPN architectures is deployment time.

With VPNs, onboarding a new customer typically involves multiple steps across teams and systems, often stretching from days to weeks depending on customer network complexity.

NaaS platforms streamline this process by allowing customers to deploy a preconfigured connector that automatically establishes secure connectivity to the SaaS provider’s network layer. In most cases, onboarding shifts from a multi-day project to a same-day or even same-hour operation. Faster deployment directly improves time-to-value for customers and reduces friction in the sales and implementation cycle.

Scalability Curves Across 10, 100, and 1,000 Endpoints

Scalability is where architectural differences become most visible.

VPN environments tend to scale in steps, requiring periodic infrastructure upgrades, re-architecture, or gateway expansion as endpoint counts grow. Each scaling event introduces risk, downtime, and unplanned cost.

NaaS platforms are built on cloud-native control planes that scale horizontally by design. Adding new customers or endpoints does not require resizing gateways or redesigning network topology. As a result, SaaS providers experience predictable growth patterns across:

• Tens of customer environments during early-stage adoption
• Hundreds of endpoints during growth phases
• Thousands of endpoints at enterprise or global scale

This linear scalability allows networking deployment and maintenance to fade into the background instead of becoming a recurring operational constraint.

Quantifying Operational Overhead

Operational burden is often underestimated when evaluating connectivity models. VPN-based SaaS connectivity requires ongoing human intervention for tasks such as access changes, troubleshooting intermittent tunnels, customer firewall coordination, and security audits.

NaaS reduces this overhead by centralizing policy, monitoring, and access control in a single platform. Routine tasks become automated, visibility improves across all customer connections, and support teams spend less time diagnosing network-specific issues. Over time, this translates into fewer escalations, faster resolution times, and a smaller networking footprint within the SaaS organization.

Annual Total Cost of Ownership Comparison

When evaluating annual TCO, VPN architectures often appear inexpensive initially due to low software licensing costs. However, these savings erode as scale increases.

Hidden VPN costs typically include infrastructure upgrades, third-party security tools, increased support staffing, and customer onboarding labor. NaaS platforms consolidate many of these functions into a single service, shifting spend from unpredictable operational costs to a more transparent subscription model.

For SaaS providers, this predictability is critical. Stable networking costs make it easier to forecast margins, price enterprise offerings, and support long-term growth without constant re-architecture.

Security Architecture Differences That Matter

Security models differ significantly between VPNs and NaaS.

VPNs commonly rely on implicit trust once a tunnel is established, often granting broad network visibility. This model increases risk in multi-tenant SaaS environments.

NaaS adopts a zero-trust mindset, where each connection is authenticated, segmented, and restricted to only the services required. Customer environments remain isolated from one another, and access policies are enforced centrally. This architecture aligns better with modern compliance expectations and reduces the impact of credential compromise or misconfiguration.

Practical Migration from VPN to NaaS

Migrating from VPN-based customer connectivity to NaaS does not require a disruptive cutover. Most SaaS providers adopt a phased approach, onboarding new customers directly onto NaaS while gradually transitioning existing customers.

Because NaaS operates independently of traditional VPN infrastructure, both models can coexist during migration. This allows teams to validate performance, security, and operational improvements incrementally while minimizing risk to existing customers.

See how Trustgrid is used to replace VPN-based customer connectivity with a centrally managed Network as a Service model at trustgrid.io/products. 

Frequently Asked Questions

NaaS uses preconfigured connectors and centralized control planes, reducing onboarding from days or weeks to hours in many cases.

Yes. NaaS typically enforces zero-trust principles, strong segmentation, and granular access controls that limit exposure compared to broad VPN access models.

NaaS is ideal for SaaS-to-customer connectivity. VPNs may still be suitable for internal employee access or legacy use cases, but they are not optimal for large-scale customer integrations.

SaaS providers that connect to on-premises systems, regulated data, or distributed customer environments benefit the most, especially when scaling beyond dozens of customers.

Yes. By lowering operational overhead, simplifying security, and avoiding repeated infrastructure upgrades, NaaS often delivers a lower and more predictable total cost of ownership over time.