Egress Cost
Summary
What it is
The cost charged by cloud providers for data transferred out of their S3 service — to the internet, another region, or another cloud.
Where it fits
Egress cost is the economic force that shapes S3 architecture decisions. It discourages multi-cloud, encourages co-located compute, and makes data gravity a real constraint.
Misconceptions / Traps
- Egress is not just internet-bound traffic. Cross-region, cross-AZ, and VPC endpoint transfers all have cost implications, though the rates differ.
- Egress costs can represent 25-35% of total cloud spend for data-heavy workloads. Budget for it explicitly, not as a surprise.
Key Connections
- AWS S3
constrained_byEgress Cost — cloud data transfer charges - Local Inference Stack
solvesEgress Cost — keeps data and compute co-located - Tiered Storage
solvesEgress Cost — cold data stays cheap, hot data stays close - Separation of Storage and Compute
constrained_byEgress Cost — data must travel to compute scoped_toS3, Object Storage
Definition
What it is
The cost charged by cloud providers for data transferred out of their S3 service, whether to the internet, another region, or another cloud.
Relationships
Outbound Relationships
scoped_toInbound Relationships
constrained_byResources
Official AWS Architecture Blog comprehensively documenting data transfer costs across common architectures, including internet egress, cross-AZ, cross-region, and VPC endpoint scenarios.
Official AWS documentation explaining data transfer charge line items in Cost and Usage Reports, the authoritative reference for understanding egress billing.
Detailed explanation of all AWS data transfer cost categories and how egress can represent 25-35% of total cloud spend for data-heavy platforms.