Cloud Data Transfer Pricing: The Hidden Traps

Data transfer charges accumulate silently. The fix is mechanical once you know the traps.

Why transfer is opaque

Transfer pricing varies by direction, region, destination. Most engineers cannot predict cost from architecture.

Transparent pricing requires effort.

Four common traps

• 1. Cross-AZ within region.
• 2. Cross-region.
• 3. Egress to internet.
• 4. NAT gateway data processing.

Avoidance patterns

Cross-AZ: topology-aware service mesh; keep traffic in same AZ.

Cross-region: avoid unless required; replicate sparingly.

Egress: CloudFront/CDN for cache hit ratio.

NAT: VPC endpoints for AWS-service-to-service.

Quantifying impact

Cross-AZ at scale: $0.01-0.02/GB. 1 PB/month = $10-20k.

NAT processing: $0.045/GB. 100 GB/day = $135/month.

Each adds up.

Antipatterns

• Service mesh ignoring AZ. Cross-AZ baked in.
• NAT for AWS service traffic. Use endpoints.
• No CDN for static. Origin paid every request.

What to do this week

Three moves. (1) Apply this lever to your highest-spend workload. (2) Measure the dollar impact for one month. (3) Roll the practice out to the next two services if the savings hold.