Is your AWS NAT Gateway the silent killer of your monthly cloud budget? Many DevOps teams find that data processing fees often exceed the cost of the actual EC2 instances, turning a simple networking component into a massive financial drain.
For most US-based enterprises, these charges stem from a lack of architectural alignment rather than actual internet traffic. By understanding how AWS bills for NAT and implementing specific VPC endpoint strategies, you can slash your networking spend without sacrificing performance or security.
The anatomy of NAT Gateway charges
To optimize your spend, you must first understand the triple-taxation model AWS applies to NAT Gateways. In a standard region like US East (Ohio), you are billed on three distinct dimensions:
- Hourly uptime: You pay $0.045 per hour for every NAT Gateway you have provisioned.
- Data processing: You are charged $0.045 for every GB of data that passes through the gateway.
- Outbound data transfer: You pay $0.09 per GB for data actually leaving the AWS network for the public internet.
The most dangerous factor is the data processing fee. Unlike standard AWS egress costs, which apply to traffic leaving the region, NAT processing fees apply to all traffic passing through the gateway. This includes traffic destined for other AWS services in the same region, such as S3 or ECR. For instance, a containerized workload pulling 178,000 GB of images from ECR through a NAT Gateway can rack up over $8,010 monthly in processing charges alone.
Replacing NAT traffic with VPC endpoints
The most effective way to eliminate NAT Gateway fees is to ensure your traffic never hits the gateway in the first place. AWS provides VPC endpoints that allow private communication with AWS services at a significantly lower cost.
Gateway endpoints for S3 and DynamoDB
Gateway endpoints should be your first line of defense because they are entirely free. There is no hourly charge and no data processing fee associated with them. If your private instances are communicating with S3 or DynamoDB through a NAT Gateway, you are essentially paying a “convenience tax” that can be removed by simply updating your VPC route tables to point to a Gateway endpoint.
Interface endpoints via AWS PrivateLink
For services like ECR, Kinesis, or Secrets Manager, you must use Interface endpoints. While these carry a small hourly fee of $0.01 per hour per ENI, their data processing fee is only $0.01 per GB. Compared to the $0.045 per GB charged by a NAT Gateway, this represents a 78% reduction in data processing costs. Moving a high-volume container workload to Interface endpoints can often save thousands of dollars per month.
Optimizing egress patterns and AZ alignment
NAT Gateways are Availability Zone (AZ) specific. If an EC2 instance in one zone sends traffic through a NAT Gateway in another zone, you are hit with both the NAT processing fee and a $0.01/GB cross-AZ data transfer charge.
To avoid this, you should deploy a NAT Gateway in each AZ where you have private subnets and ensure your routing is local to that zone. While this increases your fixed hourly uptime costs, the savings on cross-AZ transfer fees often outweigh the expense in high-traffic environments. Furthermore, you should evaluate if your private instances truly need a NAT Gateway. For instances that only communicate with other internal services, a purely private subnet utilizing the correct VPC endpoints is both more secure and significantly cheaper.
Monitoring and alerting on NAT spend
You cannot optimize what you do not measure. You should use AWS Cost Explorer to filter your “EC2-Other” category and identify the specific NAT Gateway resources driving your costs. Because NAT charges are often driven by sudden spikes in data – such as a misconfigured log export or a massive data migration – static monthly budgets are rarely enough to catch waste in real-time.
Implementing AWS Cost Anomaly Detection allows you to receive alerts when NAT processing fees deviate from your historical baseline. By integrating these alerts into Slack or Jira, your engineering team can identify the specific microservice or instance responsible for a traffic surge before it impacts your end-of-month invoice.
Automating networking optimization with Hykell
Redesigning VPC architectures and managing endpoint route tables is a manual, error-prone process that consumes valuable engineering cycles. Hykell provides automated cloud cost optimization specifically designed to identify these networking inefficiencies and fix them on autopilot.
The Hykell platform performs deep cloud cost auditing to detect when traffic patterns justify the implementation of VPC endpoints or architectural shifts. By operating on a “pay-from-savings” model, Hykell ensures that your AWS infrastructure is always running at peak efficiency without requiring your DevOps team to manually hunt for unassociated Elastic IPs or underutilized NAT Gateways.
If you are ready to see how much of your networking spend is actually waste, you can start by identifying potential savings with the Hykell automated platform, which typically helps organizations reduce their overall AWS bills by up to 40% through continuous infrastructure and rate optimization.