Is your NAT Gateway quietly becoming the most expensive component of your AWS architecture? While convenient for providing internet access, routing all your internal AWS service traffic through a NAT Gateway can inflate your networking spend by hundreds of percent compared to VPC endpoints.
The hidden cost of the NAT Gateway convenience tax
Many engineering teams rely on NAT Gateways because they are easy to set up and provide a single exit point for private subnets. However, the convenience comes with a high price tag. AWS bills NAT Gateways using a three-pronged approach: an hourly uptime fee of approximately Amazon VPC pricing $0.045 per hour in US East regions, outbound data transfer rates, and a significant data processing charge of $0.045 per gigabyte.
This data processing fee is where AWS data transfer costs often spiral out of control. Because this fee applies to all traffic passing through the gateway – including traffic destined for other AWS services like Amazon S3, ECR, or DynamoDB – high-bandwidth workloads generate thousands of dollars in processing fees for data that never even leaves the AWS network. For example, a containerized application pulling 100 TB of images or data through a NAT Gateway incurs $4,500 in processing charges alone, even before accounting for uptime or egress.
Gateway endpoints: The free alternative for S3 and DynamoDB
The most immediate way to reduce your networking bill is to implement Gateway VPC Endpoints for Amazon S3 and Amazon DynamoDB. Unlike almost every other networking component in AWS, Gateway VPC Endpoints are provided at no additional charge. There is no hourly fee and, crucially, no data processing fee.
By updating your VPC route tables to direct S3 and DynamoDB traffic through a Gateway endpoint, you effectively bypass the NAT Gateway. This simple architectural shift removes the $0.045 per GB processing fee for these high-volume services. Hykell often finds that for data-heavy organizations, this single change can significantly reduce AWS NAT Gateway costs by 80% or more without requiring any changes to application code.
Interface endpoints and the 78% processing discount
For services that do not support Gateway endpoints – such as SNS, SQS, Kinesis, or ECR – AWS offers Interface VPC Endpoints powered by AWS PrivateLink. While these endpoints carry a cost, the trade-off is often highly favorable for high-volume environments. Interface endpoints are generally billed at AWS PrivateLink Pricing $0.01 per hour per Availability Zone and $0.01 per GB for data processing.
When you compare the $0.01 per GB processing fee of an Interface endpoint to the $0.045 per GB fee of a NAT Gateway, you are looking at a 78% reduction in data processing expenses. The decision to switch depends entirely on your traffic volume. If a specific service processes enough data that the $0.035 per GB savings exceeds the approximately $7.20 monthly uptime cost of the endpoint, the switch is financially optimal. Additionally, using Interface endpoints helps you maintain AWS VPC performance optimization by keeping traffic on the AWS private backbone, which reduces latency and exposure to the public internet.
Calculating the architectural tipping point
Deciding between NAT Gateways and VPC endpoints requires evaluating the tipping point where hourly fees are offset by processing savings. Because NAT Gateways are often deployed in each Availability Zone to avoid inter-AZ data transfer charges, which cost $0.01 per GB in each direction, the fixed costs can accumulate quickly.
If your private instances only need to communicate with AWS services and do not require general internet access for software updates or external APIs, you can eliminate NAT Gateways entirely. This purely private architecture is both more secure and significantly cheaper. However, if you must maintain a NAT Gateway for external traffic, you should still offload high-volume AWS service traffic to endpoints to minimize the processing throughput on the gateway.
Automating networking optimization with Hykell
Manually auditing every route table and cross-referencing data transfer logs to find these savings is a labor-intensive process that most DevOps teams cannot prioritize. Hykell provides automated cloud cost optimization that identifies these inefficiencies for you. Our platform monitors your real-time usage patterns to determine exactly where VPC endpoints would provide the highest ROI, helping you capture the 40% savings we typically deliver to our clients.
Hykell operates on a pay-from-savings model, meaning we only succeed when your infrastructure becomes more efficient. We handle the deep dive into your networking architecture and rate optimization on autopilot, allowing your team to focus on building features rather than hunting for hidden convenience taxes in your AWS bill. To see exactly how much your NAT Gateway is overcharging you and discover your potential savings, use the Hykell cost savings calculator today.
