Introduction
If you’ve spent any time architecting Azure solutions, you’ve almost certainly hit the moment where you need to lock down access to a PaaS service – an Azure Storage account, SQL Database, or Key Vault – and been confronted with two options: Private Endpoint or Service Endpoint. Both exist to secure your traffic. Both keep data off the public internet. But they work very differently, have different cost implications, and suit different scenarios.
This guide cuts through the confusion with a clear, technically accurate comparison, real-world decision criteria, and concrete examples to help you pick the right approach – every time.
📌 Quick Answer Use Private Endpoint when you need complete network isolation, on-premises access, or handle regulated/sensitive workloads. Use Service Endpoint when you want a simpler, free setup for VNet-only traffic and full isolation is not a strict requirement.
Understanding the Fundamentals
What is a Service Endpoint?
Service Endpoints were Microsoft’s first solution for securing PaaS access from a virtual network. When you enable a Service Endpoint on a subnet, Azure adds an optimised route to the subnet’s route table so that traffic destined for the PaaS service travels over the Azure backbone network rather than the public internet.
However – and this is the critical detail many architects miss – the PaaS resource itself still has a public IP address. You’re not bringing the service into your VNet. You are simply telling the service’s firewall: “only allow traffic originating from this specific subnet.” The service endpoint traffic does leave your VNet, it just never touches the public internet (ISP network).
⚠️ Common Misconception Service Endpoints do NOT give the Azure service a private IP address. DNS entries for the service remain unchanged and still resolve to public IPs. The traffic takes the Azure backbone route – but it originates from the source subnet’s private IP, not a private IP of the PaaS resource itself.
What is a Private Endpoint?
Private Endpoint is a newer, more comprehensive solution built on Azure Private Link. Instead of routing traffic to the PaaS service’s public endpoint over the backbone, a Private Endpoint injects the PaaS resource directly into your VNet by allocating it a private IP address from your address space.
From that point on, all traffic to the resource – whether from within your VNet, across a peered VNet, or from on-premises via ExpressRoute or VPN – stays entirely within the Microsoft network and never traverses the public internet or backbone in the traditional sense. The PaaS resource effectively becomes part of your private network.
This requires two additional configuration steps that Service Endpoints do not: a network interface (NIC) is created in your VNet, and a Private DNS Zone must be configured so that the service’s public FQDN resolves to the private IP address instead of the public one.
Side-by-Side Comparison
The table below summarize the key differences across the dimensions that matter most to Azure architects:
| Feature | Private Endpoint | Service Endpoint |
| IP Address | Private IP from your VNet (e.g. 10.0.0.5) | Public IP (traffic stays on backbone) |
| Traffic Path | Stays entirely within your VNet – never touches public internet | Leaves VNet but routes via Azure backbone, not public internet |
| DNS Change Required | Yes – Private DNS Zone must be configured | No – DNS entries remain unchanged |
| On-Premises Access | Yes – via ExpressRoute or VPN | No – on-premises clients cannot use Service Endpoints |
| Network Scope | Available across peered VNets | Subnet-only – not transitive across VNet peering |
| Cost | Higher – NIC + Private DNS Zone charges apply | Free to enable |
| Setup Complexity | Higher – NIC, DNS Zones, NSG rules needed | Low – enable on subnet, add VNet to service firewall |
| Compliance / Isolation | Full isolation – ideal for regulated workloads | Good – but resource still has public endpoint |
| Services Supported | Broad – Storage, SQL, Key Vault, AKS, and 100+ more | Limited set (Storage, SQL, Key Vault, Service Bus, etc.) |
| Microsoft Recommendation | Preferred for sensitive/production workloads | Suitable when full isolation is not required |
Deep Dive: Key Differences That Actually Matter
1. Traffic Path and Isolation
This is the most fundamental difference. With a Service Endpoint, your VNet’s traffic leaves the virtual network boundary and reaches the PaaS service over the Azure backbone. The destination IP is still a public IP. With a Private Endpoint, traffic never leaves the private address space – the destination is a private IP (e.g. 10.0.0.5) that lives in your VNet. Disabling public access on a resource with a Private Endpoint does not remove the public endpoint – it simply sets the firewall to block all inbound public traffic. This is why you receive a 403 Forbidden, not a 404 Not Found, when attempting public access.
2. DNS Configuration – The Biggest Operational Difference
Service Endpoints require zero DNS changes. The storage account FQDN (e.g. mystorageaccount.blob.core.windows.net) continues to resolve to its public IP, and Azure routes traffic over the backbone based on the subnet route.
Private Endpoints require DNS reconfiguration. Azure creates a CNAME record that resolves the public FQDN to a privatelink subdomain (e.g. mystorageaccount.privatelink.blob.core.windows.net), which in turn resolves to the private IP. You must configure an Azure Private DNS Zone linked to your VNet to make this work. In hybrid environments with on-premises DNS servers, this means ensuring your DNS forwarders correctly resolve privatelink FQDNs – a common source of connectivity issues.
3. On-Premises Connectivity
Private Endpoints win clearly here. Because the PaaS resource has a private IP, on-premises clients connected via ExpressRoute or VPN can reach it directly – provided DNS is set up correctly. Service Endpoints offer no equivalent capability – they only work for resources within the Azure VNet subnet where the endpoint is enabled.
4. Network Scope and VNet Peering
Service Endpoints are subnet-scoped and non-transitive. If you have workloads in multiple subnets, you must enable the Service Endpoint on each subnet individually. They do not propagate across VNet peering connections, meaning resources in a peered VNet cannot leverage another VNet’s Service Endpoint.
Private Endpoints, by contrast, are accessible from anywhere that has IP connectivity to the VNet – including peered VNets (subject to NSG rules), on-premises networks, and other connected environments. This makes them far more flexible in hub-and-spoke architectures.
5. Cost
Service Endpoints are free to enable. There is no charge for the endpoint itself – you only pay for the data processed by the underlying service.
Private Endpoints incur charges: you pay per endpoint per hour plus a data processing fee. You also pay for the Private DNS Zone(s) required to make it work. For high-volume workloads or environments with many Private Endpoints across multiple services, these costs add up and should be factored into your architecture decisions.
When to Use Service Endpoints
Service Endpoints are the right choice when:
- Your workloads are entirely within Azure VNets and you have no requirement for on-premises access to the PaaS service.
- You need to restrict PaaS access quickly with minimal configuration overhead – no DNS zones, no NICs.
- Cost optimisation is a priority and the workload does not handle highly regulated or sensitive data.
- You are implementing a baseline security posture and plan to migrate to Private Endpoints as requirements mature.
- The service in question does not yet support Private Endpoints (though this list has shortened significantly).
💡 Real-World Example A development/test environment with Azure Storage accounts where developers access resources from within Azure VMs in the same VNet. Full isolation is not required, there’s no on-premises access, and cost sensitivity is high. Service Endpoint is the pragmatic choice.
When to Use Private Endpoints
Private Endpoints are the right choice when:
- You handle sensitive data governed by compliance frameworks such as PCI-DSS, HIPAA, ISO 27001, or UAE PDPL.
- On-premises systems need to access Azure PaaS services over ExpressRoute or VPN.
- Your architecture uses hub-and-spoke and you need centralised, consistent access to shared PaaS resources.
- You require complete elimination of public endpoint exposure for a resource (combined with disabling public access).
- You are building production workloads where the additional operational overhead of DNS management is justified by the security gain.
💡 Real-World Example A financial services firm storing transaction data in Azure SQL Database, accessed both from Azure-hosted application servers and from on-premises reporting tools over ExpressRoute. A Private Endpoint with a Private DNS Zone and public access disabled is the correct architecture.
Can You Use Both Together?
Yes – and in some architectures, you should. There is no technical restriction preventing you from having both a Service Endpoint and a Private Endpoint configured for the same service in the same environment. However, in practice, if you have deployed a Private Endpoint and disabled public access, the Service Endpoint becomes redundant for that resource.
A common migration pattern is to start with Service Endpoints for speed of deployment, then incrementally migrate to Private Endpoints as workloads are hardened. During the transition period, both may coexist.
Decision Framework
Use this simple decision tree when evaluating which endpoint type to deploy:
| If your requirement is… | Choose |
| On-premises access to Azure PaaS via ExpressRoute/VPN | ✅ Private Endpoint |
| Complete network isolation with no public endpoint exposure | ✅ Private Endpoint |
| Regulated workload (PCI, HIPAA, ISO 27001) | ✅ Private Endpoint |
| Hub-and-spoke architecture with shared PaaS services | ✅ Private Endpoint |
| Simple VNet-only restriction, low cost priority | ✅ Service Endpoint |
| Dev/Test environments with no compliance requirements | ✅ Service Endpoint |
| Quick setup with zero DNS configuration | ✅ Service Endpoint |
| Access needed from multiple subnets across peered VNets | ✅ Private Endpoint |
Common Pitfalls to Avoid
With Private Endpoints
- Forgetting to configure Private DNS Zones – the most common reason Private Endpoints appear to not work.
- Not accounting for DNS resolution in hybrid environments – on-premises resolvers must be able to forward privatelink.* queries to Azure DNS.
- Assuming disabling public access is automatic – it must be explicitly configured after deploying the Private Endpoint.
- Overlooking NSG rules – Private Endpoint NICs now support NSG enforcement; ensure your NSG policies align with your security posture.
With Service Endpoints
- Enabling on all subnets globally – be intentional about which subnets genuinely need the endpoint.
- Treating Service Endpoints as equivalent to Private Endpoints from a compliance perspective – they are not; regulators increasingly require Private Endpoints for sensitive data.
- Assuming they work across VNet peers – they do not; each peered VNet must configure its own Service Endpoints.
Summary
Both Service Endpoints and Private Endpoints are valid tools in the Azure networking toolkit – they are not simply “old vs new” or “worse vs better.” The right choice depends on your isolation requirements, connectivity needs, compliance obligations, and operational maturity.
As a general principle: if you are building production workloads handling sensitive or regulated data, invest in Private Endpoints. The DNS overhead is a one-time configuration cost, and the security and compliance gains are substantial. For internal tooling, dev/test environments, or situations where on-premises connectivity is not required, Service Endpoints remain a practical and cost-effective choice.
🔑 Key Takeaway Microsoft itself recommends Private Endpoints for sensitive workloads. But Service Endpoints, when configured correctly, provide strong security for many scenarios. Know your requirements, apply the decision framework above, and document your choice rationale for your architecture review board.
P.S. Modern AI tool has been used for creating some of the content. Technical validation and proofing are done by the author.