Three New Serverless Vector Stores on AWS, Compared Through a Starter Project

The author needed a small private document collection to be searchable inside a serverless application, and found that AWS's earlier OpenSearch Serverless required a minimum spend of roughly $200 per month even in dev-test mode. Since then AWS has introduced three services that scale to zero: OpenSearch Serverless NextGen, S3 Vectors, and vector indexing in DynamoDB. The article compares their differences, costs, and tradeoffs, and the author concludes that OpenSearch Serverless NextGen is hard to beat. A CDK TypeScript starter project loads the same document chunks from a nine-page extract of the UK Aeronautical Information Publication into all three stores to test retrieval. The comparison focuses on technical feasibility rather than a formal benchmark, and the approach is presented as applicable to manuals, policies, and other private documentation.