15 articles on data transfer — what drives the cost, how it is priced, and where the savings actually are.
Traffic between availability zones costs about $0.01 per GB each way, while traffic between regions runs roughly $0.02 per GB or more. Both are easy to trigger accidentally and both compound at scale. Here is how the two taxes differ and how to avoid them.
Traffic between resources over private IPs in the same AZ is free, but the same traffic over public or Elastic IPs is charged even within a region. Using the wrong address turns free traffic into a per-GB bill. Here is how to keep it free.
Data egress (traffic leaving AWS to the internet, and between regions and AZs) is one of the most surprising and controllable line items. This checklist walks through the highest-impact ways to cut it, from CDN caching to architecture.
Traffic between availability zones inside the same region is not free. At roughly a cent per GB in each direction, cross-AZ transfer quietly adds up for chatty microservices, replicated databases, and Kafka clusters. Here is how it is billed and how to cut it.
Some cloud data transfers are free (inbound, same-AZ private traffic) and some are expensive (egress to the internet, cross-region, cross-AZ). Knowing which is which is essential to avoiding surprise bills. Here is the map.
A content delivery network bills mostly for data transfer out and requests, and the rates vary by provider and region. Here is how CloudFront, Google Cloud CDN, and Azure CDN compare, and how to keep CDN cost predictable.
Replicating data across regions for durability or latency adds cross-region data transfer charges plus duplicated storage, and the transfer is often the bigger surprise. Here is how cross-region replication is priced and how to control it.
Data transfer out, egress to the internet, is one of the least understood and most surprising cloud charges. Inbound is usually free, outbound is not, and it scales with traffic and region. Here is how egress pricing works and how to cut it.
Images are often the largest bytes a site serves, so optimizing them, right-sizing dimensions, modern formats like WebP and AVIF, and compression, cuts egress and storage substantially. Here is where image optimization saves cloud cost.
Compression shrinks the bytes you store, transfer, and scan, and cloud bills those bytes. Compressing data can cut storage, egress, and query cost at once, for a little CPU. Here is where compression pays and where it does not.
Compute and storage have converged, but data transfer hasn't. Here's the shared structure (ingress free, egress tiered, cross-region charged), where AWS/Azure/GCP diverge, and the universal levers to cut it.
Azure egress is free for the first 100 GB/month, then tiered ~$0.087/GB; ingress is free. Here's the egress map, the patterns that drive the bill, and how a CDN and region co-location cut it.
VNet peering has no hourly fee but charges ~$0.01/GB each direction (more for global). It bills on both sides. Here's where the cost hides in hub-and-spoke and chatty services, and how to cut it.
GCP charges for egress to the internet, between regions, and even between zones, but not ingress or same-zone traffic. Here's the egress map, the three patterns that drive the bill, and how to cut it.
The most opaque part of the AWS bill, broken down. Internet egress, cross-region, cross-AZ, NAT processing, CloudFront, VPC endpoints. The five biggest cost surprises and how to fix them.