S3 as Container Registry

Consider using S3 as a lower-cost alternative to ECR for hosting container images.

Why it matters

ECR charges $0.10 per GB-month for storage, but there’s an alternative: hosting container images directly in Amazon S3 at $0.023 per GB-month—a ~77% reduction in storage costs.1

Container images are collections of tar archives following the OCI specification, which means they can be stored in S3 and pulled with the right tooling. If you rely on ECR’s registry features like vulnerability scanning, lifecycle policies, or replication, you’ll need to implement workarounds or alternative solutions.

Adolfo Ochagavía wrote an excellent technical exploration of this approach, demonstrating how to use S3 as a container registry.2

Quick comparison

Storage for 100 GB of images:

  • ECR: $10.00/month
  • S3 Standard: $2.30/month

Keep in mind you’ll need custom tooling and won’t have built-in registry features, but for cost-sensitive environments with simple needs, S3 can be a viable alternative.

Resources

Footnotes

  1. Amazon S3 pricing ↩

  2. Using S3 as a Container Registry by Adolfo Ochagavía ↩