Amazon OpenSearch Service vs Azure Cosmos DB for NoSQL
Amazon OpenSearch Service
aws.amazon.com
Azure Cosmos DB for NoSQL
azure.microsoft.comSide by side
| Figure | Amazon OpenSearch Service | Azure Cosmos DB for NoSQL |
|---|---|---|
| Price from | — | Free |
| Free plan | — | Yes |
| Free trial | — | Yes |
| Open source | — | — |
| Web | Yes | — |
| API | Yes | Yes |
| Self-hosted | — | Yes |
| Plans published | 1 | 10 |
| Spec score · Ai Databases | 7.5 (#24) | 8.1 (#12) |
| Availability | AWS states a 99.99% SLA for highly available, multi-AZ deployments with standby. | The product page states that NoSQL data has SLAs including less than 10 millisecond read and write latency and 99.999 percent availability. |
| Founded | 2006 | 1975 |
| Security | The service supports encryption at rest and in transit, and granular permissions for indices, documents, and fields. | Microsoft recommends private endpoints, disabling public network access, and client-side encryption with Always Encrypted for sensitive data. |
| Vector search | Its vector engine supports k-NN and ANN search using HNSW and IVF implementations, including searches over billions of high-dimensional vectors. | Yes |
Plans
Azure Cosmos DB for NoSQL
- Free tierFree
- 30-day free trialPriced on request
- Standard provisioned throughputPriced on request
- Standard provisioned throughputPrice not published
- Autoscale provisioned throughputPriced on request
- Autoscale provisioned throughputPrice not published
- ServerlessPriced on request
- ServerlessPrice not published
- Azure Cosmos DB free tierFree
- Azure Cosmos DB for NoSQL — standard provisioned throughputPrice not published
In their own words
Amazon OpenSearch Service
Amazon OpenSearch Service has no write-up on Specifiction yet; its figures are above.
Azure Cosmos DB for NoSQL
Azure Cosmos DB for NoSQL is a fully managed cloud database built around schema-agnostic JSON documents and SQL-like querying. It supports global data distribution, multi-region writes, and automatic failover, with configurable consistency controls and transactions. Search includes vector and hybrid similarity capabilities for workloads such as retrieval-augmented generation and AI agents. Throughput can use standard provisioned, autoscale provisioned, or serverless models. The service lists SDKs for.NET, Java, JavaScript/Node.js, Python, Go, and Rust. Its change feed can support event-driven architectures and streaming pipelines using Azure Functions and Spark; no-ETL analytical workflows are available through Azure Synapse Link or Fabric mirroring. Microsoft states that NoSQL data has service-level agreements including less than 10 millisecond read and write latency and 99.999 percent availability. A free tier includes 1,000 RU/s and 25 GB of storage for one account per Azure subscription, and a 30-day trial is listed. The Azure Cosmos DB emulator provides a no-cost local development environment for Windows or Linux. The pricing page notes that the selected compute pricing model and API cannot be changed after selection.