Azure Cosmos DB for NoSQL vs Azure DocumentDB

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.

Azure DocumentDB is a document database for applications using BSON and JSON. It supports transactions and vector search, with a maximum document size of 16.0 MB. Deployment options include managed cloud and another deployment model; listed platforms are Linux, macOS, and Windows. The Free Tier is billed Free for the life of the cluster and includes 32 GB of storage and one free database server per subscription. Fixed M-series plans provide different node capacities: M10 starts with 1 vCore and 2 GiB of memory per node, while M300 lists 96 vCores and 384 GiB per node. Between those are configurations with varying memory and compute, including burstable vCores on M25. M200-Autoscale is billed hourly according to usage and offers up to 64 vCores and 256 GiB of memory. Prices for the listed paid tiers are displayed as $-, with actual amounts depending on region and currency. This gives prospective users concrete capacity specifications alongside the free cluster allowance.