Azure DocumentDB vs Firestore

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.

Firestore is a fully managed, serverless document database for building AI, web, and mobile applications. It stores flexible JSON data and supports vector search, full-text search, geospatial queries, and ACID transactions on JSON or BSON-compatible documents. Client SDKs for Android, iOS, and web provide real-time updates and automatic syncing for offline access. Firestore can replicate data across multiple regions with strong consistency; multi-region deployments have a stated 99.999% SLA-backed availability. Integrations named for generative AI application work include Google AI Studio, remote MCP, LangChain, and LlamaIndex. Identity controls connect with Cloud IAM, Cloud Identity Platform, and Firebase Authentication. Data is encrypted before it is written to disk, with customer-managed keys available through Cloud KMS. The free quota applies to one database per project and includes 1 GiB of storage, daily read, write, and delete allowances, and 10 GiB monthly outbound transfer. New customers receive $300 in credits, separate from that quota. Server client libraries bypass Firestore Security Rules, so server access needs IAM controls.