AWS PrivateLink is an AWS networking technology that allows applications in one VPC to privately connect to supported AWS services, services hosted by other AWS accounts, SaaS applications, and certain VPC resources without sending traffic through the public internet.
How Does AWS PrivateLink Work?
The most common implementation uses an interface VPC endpoint. When you create one, AWS places endpoint network interfaces with private IP addresses into the selected subnets. Applications communicate with the endpoint, and traffic remains on the AWS network instead of traversing the public internet.
A simplified flow is:
Application → VPC Endpoint → AWS PrivateLink → Endpoint Service → Service
PrivateLink can also allow an organization to publish its own service to selected AWS customers or accounts. A service provider typically uses a Network Load Balancer as the front end for its endpoint service, while consumers create interface VPC endpoints to connect to it.
Why Is PrivateLink Useful?
PrivateLink is particularly valuable when organizations want to reduce public network exposure and control which services their private workloads can access.
Common use cases include:
- Accessing AWS services from private subnets
- Connecting applications between different AWS accounts
- Privately consuming SaaS services
- Sharing internal services with other teams or accounts
- Supporting security and compliance requirements
- Building hybrid or multi-account architectures
Endpoint policies and security groups can also be used to control access to interface endpoints.
PrivateLink vs VPN or VPC Peering
PrivateLink is different from technologies such as VPC Peering and VPN. Peering provides network-level connectivity between VPCs, while PrivateLink is generally used to expose specific services or resources privately without giving consumers broad network access to the provider's VPC.
This makes PrivateLink useful when a provider wants to expose a service rather than an entire network.
Important Cost Consideration
PrivateLink is not free. Interface endpoints can incur hourly endpoint charges for each Availability Zone and data-processing charges based on the amount of data transferred through the endpoint.
For production environments, teams should therefore consider endpoint placement, Availability Zone coverage, expected traffic, DNS configuration, security groups, and endpoint policies when designing the architecture.
Final Thought
AWS PrivateLink is best understood as a way to provide private, controlled service connectivity without exposing the service to the public internet. For DevOps and cloud engineers, understanding PrivateLink is especially important when designing secure multi-account, microservices, SaaS, and hybrid-cloud architectures.