AWS PrivateLink vs. VPC Gateway Endpoint
AWS provides multiple ways to connect to its services privately, without exposing traffic to the public internet. Two primary options for secure private connectivity are AWS PrivateLink and VPC Gateway Endpoints.
Both allow you to communicate with AWS services or third-party services without going through the public internet, but they serve different purposes and work in distinct ways. Let’s break them down.
1. AWS PrivateLink
Overview
AWS PrivateLink enables private connectivity between VPCs and AWS services, third-party services, or your own applications hosted in another VPC. It routes traffic entirely within the AWS network without requiring NAT gateways, VPNs, or internet gateways.
How It Works
- PrivateLink exposes an AWS service, third-party service, or your own application as an Elastic Network Interface (ENI) with private IPs in your VPC.
- A VPC Endpoint Interface (powered by PrivateLink) connects to the service via private connectivity.
- Traffic never leaves the AWS backbone network, making it secure and low-latency.
Use Cases
- Access AWS services privately: E.g., AWS S3, Kinesis, and DynamoDB using Interface Endpoints.
- Connect to third-party SaaS services: Many AWS Marketplace vendors expose their services via PrivateLink.
- Cross-VPC connectivity without peering: Share services across different VPCs without setting up complex VPC peering.
- Hybrid Cloud: Use PrivateLink to expose your applications running on AWS to on-premises clients securely.
Pros
✅ Works across AWS accounts and regions via VPC Peering and Transit Gateway.
✅ Private connectivity—data never leaves AWS’s private network.
✅ No need for IGW, NAT, or VPN—saves cost and complexity.
✅ Supports third-party and custom services, not just AWS-native services.
✅ More granular control over who can access the service via Security Groups.
Cons
❌ More expensive than VPC Gateway Endpoints due to per-hour and data transfer costs.
❌ Limited AWS services support PrivateLink natively (e.g., S3 and DynamoDB don’t use it).
❌ Requires changes to DNS resolution to use private service endpoints effectively.
2. VPC Gateway Endpoint
Overview
A VPC Gateway Endpoint enables private connectivity to AWS services like S3 and DynamoDB, allowing instances in a VPC to access these services without using an internet gateway (IGW), NAT Gateway, or VPN.
How It Works
- Gateway Endpoints create static routes in your VPC route table that direct traffic for AWS services to the private AWS network instead of going through the internet.
- Unlike PrivateLink, a Gateway Endpoint does not create an ENI inside your VPC.
Use Cases
- Access Amazon S3 and DynamoDB privately without routing traffic over the internet.
- Reduce data transfer costs by avoiding NAT Gateway charges for accessing AWS services.
- Increase security by restricting access to AWS services without needing public IPs.
Pros
✅ Completely free—no per-hour charges; you only pay for the data transferred.
✅ Simpler to configure—just update the route table of the VPC.
✅ Highly scalable—no need to manage ENIs or security groups.
✅ No bandwidth constraints—does not rely on ENI limits.
Cons
❌ Only supports S3 and DynamoDB—cannot be used for other AWS services.
❌ Does not support third-party services—only AWS-managed services.
❌ Requires modifying route tables—less flexible than PrivateLink for fine-grained access control.
Key Differences: AWS PrivateLink vs. VPC Gateway Endpoint
| Feature | AWS PrivateLink 🌐 | VPC Gateway Endpoint 🚀 |
|---|---|---|
| Type | Interface Endpoint (ENI-based) | Gateway Endpoint (Route-based) |
| Connectivity | Connects to AWS services, third-party SaaS, or custom applications | Connects only to Amazon S3 & DynamoDB |
| Traffic Routing | Uses ENI in your subnet | Uses VPC route tables |
| Services Supported | AWS services, SaaS providers, custom apps | Only S3 & DynamoDB |
| Cross-Region Support | ✅ Yes | ❌ No |
| Cross-Account Support | ✅ Yes (via PrivateLink sharing) | ❌ No |
| Internet Gateway/NAT Needed? | ❌ No | ❌ No |
| Security Group Control | ✅ Yes, can use security groups | ❌ No, uses route tables |
| Pricing | Paid (Per-hour + Data Transfer Fees) | Free (No per-hour cost, just data transfer) |
| Setup Complexity | More complex (ENIs, DNS, Security Groups) | Simpler (Route Table Updates) |
| Use Case | Private access to AWS services, third-party services, and internal apps | Private access to S3 & DynamoDB |
When to Use AWS PrivateLink vs. VPC Gateway Endpoint?
✅ Use AWS PrivateLink if:
- You need to access AWS services securely, but the service does not support Gateway Endpoints.
- You want to connect to third-party services (SaaS) privately (e.g., Snowflake, Datadog).
- You need to expose your own applications to other VPCs or on-premises clients without using a public IP.
- You require cross-region or cross-account connectivity via PrivateLink sharing.
✅ Use VPC Gateway Endpoint if:
- You only need to access Amazon S3 or DynamoDB.
- You want free private connectivity without per-hour charges.
- You prefer simpler configuration with just route table updates.
- You don’t need third-party services or custom applications.