OpenSearch Serverless collections are actually charged by hours?

AOSS collection pricing is $0.24 per hour. For production use cases, you would need a minimum of 2 OCU (1 OCU per AZ) for ingestion and 2 OCU for Search/query - so a total of 4 OCUs. With 720 hours (30 days, 24 hours per day), that translates to roughly $691 per month. You can see more information on pricing here https://aws.amazon.com/opensearch-service/pricing/ But, if you delete the collection, you should get charged only for the hours your AOSS collection was used.

But we recently introduced new lower entry point for Amazon OpenSearch Serverless. https://aws.amazon.com/about-aws/whats-new/2024/06/amazon-opensearch-serverless-entry-cost-half-collection-types/

With the introduction of fractional 0.5 OCU, OpenSearch Serverless can be deployed starting at just 2 OCUs for production workloads.This includes 1 OCU for primary and standby indexing nodes at 0.5 OCU each, and 1 OCU total for search across two 0.5 OCU active replica nodes in separate Availability Zones. So, you will be paying half than the classic minimum workload.

Additionally, for dev/test workloads that don't require high availability, OpenSearch Serverless offers a 1 OCU deployment option, further cutting costs in half, with 0.5 OCU for indexing and 0.5 OCU for search.