What Is a VPC Endpoint / PrivateLink, and Why Move Service Traffic Off the Public Internet

A VPC is an isolated network boundary inside the cloud where virtual machines, databases, clusters, internal services, and other parts of a project’s infrastructure live. These boundaries are usually separated intentionally, so that different products, environments, or shared infrastructure systems do not end up mixed into one large and poorly governed network.

But isolation does not eliminate the need for integration. In practice, different VPCs still need to exchange data: a shared CI/CD system deploys services across several projects, analytics is collected into a common platform, one product calls the internal API of another, and sometimes integration is needed even between the infrastructures of different companies.

That is exactly where VPC Endpoint / PrivateLink comes in. These mechanisms make it possible to connect one environment to a required service in another without unnecessarily exposing that service externally and without sending the traffic through the public Internet.

Put simply, the logic looks like this:

In practice, this is useful where the goal is not to “connect everything to everything,” but to expose access carefully to one specific service — for example, an internal API, a storage system, an analytics platform, or a shared infrastructure component.

In that sense, VPC Endpoint / PrivateLink is valuable not because “internal traffic must always be hidden,” but because cloud architectures often require precise integration between isolated environments without unnecessary network entanglement.

Why the Cloud Is Split into Separate Boundaries — and What a VPC Actually Is

Now we can calmly lay out the foundation, because without it the terminology quickly becomes confusing.

A VPC is a Virtual Private Cloud — in other words, a logically isolated virtual network inside the cloud that you define for your own needs. Inside it live virtual machines, databases, containers, internal services, and everything else that belongs to a particular part of the infrastructure. Conceptually, it is similar to a separate network domain in a data center, except that here it is built on the cloud provider’s side.

At this point, people often form an oversimplified expectation: if everything is “in one cloud,” then surely it should all live in one shared network anyway. In practice, almost nobody does that. One large VPC quickly turns into an awkward construct where different projects, environments, teams, and shared service systems all live side by side, while access rules begin spreading in every direction.

That is exactly why cloud environments are usually split into separate boundaries from the start. Not because “it looks nicer,” but because it is easier to keep the infrastructure under control that way.

For example, a company may have one product built around an online store, another around a B2B customer portal, and then a separate shared infrastructure boundary containing Git, CI/CD, monitoring, and internal utilities. Formally, all of this could be kept inside one network. But very quickly it becomes clear that these parts have different roles, different access needs, and different costs of failure.

That is why VPCs are usually separated according to very practical logic:

• By project, so that different products do not end up living in one network mess
• By environment, so that dev, test, and production do not mix without a reason
• By area of responsibility, when different teams need their own boundary
• By infrastructure role, when shared services live separately from application systems

This approach provides more than just a cleaner diagram. It makes access easier to manage, reduces the chance of accidental overlap, and makes the architecture more understandable for the team. When boundaries are separated deliberately, it becomes much easier to see who should actually be talking to whom — and who should not.

But this same neatness has a downside. The moment projects, environments, or shared service boundaries stop being fully autonomous, real integration points begin to appear between them. And that is exactly where the next question arises: when do separate VPCs still need to be connected to one another?

When Separate VPCs Still Need to Be Connected

Isolation is not there for its own sake. Its purpose is to bring order to the network. But that does not mean every boundary should live in complete separation from all the others.

In practice, different VPCs begin intersecting with one another through real operational needs fairly quickly. Projects end up sharing services, processes, and data exchange points. The issue is usually not that the architecture was “designed incorrectly,” but that separated environments naturally develop legitimate reasons to interact over time.

Most often, it looks something like this:

Across all of these scenarios, the underlying question is usually the same: how do you provide the required connectivity between environments without making the network unnecessarily messy? Sometimes that requires broader connectivity between VPCs, while in other cases access is needed only to a single specific service. That is exactly why the next step is to look at the common ways these problems are usually solved.

What Options Exist for Connecting VPCs — and Where VPC Endpoint / PrivateLink Fits In

When Peering Is the Better Fit

Sometimes two VPCs need fairly broad connectivity. Not just access to one specific service, but the ability to exchange traffic between the environments over private addresses more generally.

That is the right fit for situations where the networks need to see one another much more broadly. For example, if two projects have many internal interactions, shared components, or bidirectional requests, then narrow point-to-point access is no longer enough. In that case, it makes more sense to look toward VPC peering or other forms of network-level connectivity between the environments.

When PrivateLink Is Enough

But there is another kind of task as well. Sometimes you do not need to “stitch the networks together” as a whole — you only need access to one specific service.

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For example, one VPC may need to send events into a shared analytics platform. Or several projects may need access to an internal API that lives in a separate environment. Or one company may want to grant a partner access to only one service without exposing the rest of the network.

That is exactly where VPC Endpoint / PrivateLink looks cleaner. It does not provide broad network connectivity. Instead, it provides targeted private access to the right place, and only to the right place.

If you put the difference side by side, it looks like this:

That is what changes the logic of the decision. The question is usually not which technology is “better,” but how broad the required access really is. If the task is to connect the environments more fully, one approach makes sense. If the goal is access only to one service without fully merging the networks, the other is the better fit.

Where VPC Endpoint / PrivateLink Is Especially Useful — and Where It Should Not Be Forced Without a Real Reason

After everything we have already covered, the logic here is fairly simple: VPC Endpoint / PrivateLink is useful not “everywhere in the cloud,” but in situations where isolated environments need narrow, clear, and controlled access between them.

That is exactly why it works best where one side needs to connect carefully to a specific service in another VPC, rather than receiving broader network connectivity as part of the package.

This is easiest to see in a few common scenarios:

But this is also exactly where it becomes important not to force the technology onto every problem.

If two VPCs need not just access to one service, but broader and more persistent connectivity between several components, then PrivateLink may simply be too narrow a solution. In that case, the issue is not the tool itself — it is that the actual task is different.

The same is true for small and simple projects. If the infrastructure is compact, the number of services is small, and separate environments barely interact, this form of connectivity may introduce more complexity than real value.

There is another common mistake as well: trying to solve with PrivateLink problems that do not actually belong to the traffic path at all. It will not replace a sound access model, fix weak segmentation, or help if the team itself does not yet clearly understand which components should be talking to which others.

So the practical rule of thumb is quite straightforward: if the goal is to expose one specific service between isolated environments without granting unnecessary connectivity, then VPC Endpoint / PrivateLink is usually a very good fit. If the VPCs need broader and more permanent network communication, it is better to look at other options from the start.

Conclusion

VPC Endpoint / PrivateLink is not a universal way to connect any environments in the cloud. It is a tool for a narrower task: providing targeted access to a specific service without introducing unnecessary network connectivity.

If the goal is to connect VPCs more broadly and allow several components to exchange private traffic on a stable basis, teams usually start looking at peering or at larger transit-style designs instead. And if the service needs to be available to external users or partners at all, the more typical answer involves load balancers, API gateways, DNS-based routing, or other external entry points.

So the main question here is very simple: do you need access to one service, or do you need real connectivity between environments? The answer to that question is what determines whether PrivateLink is actually the right fit.

FAQ

Do you need to use VPC Endpoint / PrivateLink in every project?

No. In small and simple infrastructures, it may not provide meaningful value and can end up making the design more complicated instead.

How is VPC Endpoint / PrivateLink different from VPC peering?

Peering provides broader network connectivity between VPCs. PrivateLink solves a narrower problem — exposing access only to a specific service without fully connecting the environments.

Can you completely get rid of NAT when using a VPC Endpoint?

Sometimes yes, but not always. It depends on which services the application needs to reach and whether those services support private endpoints in the first place.

If a service is already protected with IAM or other controls, why also use a private endpoint?

Because these are different layers. IAM governs who is allowed to access something, while a private endpoint governs how that access travels across the network.

Is PrivateLink suitable for integration between different companies or accounts?

Yes. That is actually one of its most typical use cases. It is especially useful when one side needs access only to one specific service on the other side, without establishing broad network connectivity between the environments.

Can PrivateLink be used for your own services, not only cloud-native provider services?

Yes. In some clouds, mechanisms like this can also be used to publish your own internal services when they need to be reached privately from other VPCs or accounts.

Sources

1. AWS Docs — What is AWS PrivateLink?

2. AWS Docs — VPC Endpoints

3. Microsoft Learn — What is Azure Private Link?

4. AWS Docs — What is VPC peering?