The movement of data between cloud services, regions, availability zones, or between the cloud and the internet. Egress (data leaving a cloud) typically incurs costs; ingress (data entering) is usually free. Understanding data transfer pricing is critical for cost optimization — cross-region transfers, CDN distribution, and Direct Connect/ExpressRoute can significantly impact cloud bills.
A media company stores video files in AWS S3 us-east-1 and serves them globally. By routing delivery through CloudFront (CDN), they reduce direct S3 egress costs by 60% and lower latency for viewers worldwide.
All major cloud providers charge for moving data across certain network boundaries, especially outbound traffic to the internet and traffic between regions. Inbound internet traffic is often free, while inter-region, cross-zone, CDN, and dedicated connectivity pricing varies by provider.