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Azure Cosmos DB vs MongoDB

Azure Cosmos DB: Microsoft's globally distributed, multi-API NoSQL and vector database with SLA-backed latency. MongoDB: The default document database: flexible BSON documents, rich queries and built-in sharding.

key differences

  • Licensing: Azure Cosmos DB is proprietary (Proprietary Azure service); MongoDB is source-available (Server Side Public License v1 (Community); commercial (Enterprise)).
  • Azure Cosmos DB is built for larger datasets (Multi-PB) than MongoDB (≤ 1 PB).
  • Transactions: Azure Cosmos DB offers limited ACID; MongoDB offers full.
  • Only Azure Cosmos DB has triggers, stored procedures, columnar storage.
  • Only MongoDB has joins, materialized views, in-memory, compression.
  • Azure Cosmos DB has a serverless option; MongoDB does not.

choose azure-cosmos-db for

  • +Globally distributed user and session data
  • +IoT telemetry and device state
  • +Chat history and memory for AI agents
  • +Retail carts, catalogs and personalization

best at · OLTP, IoT, Sessions

choose mongodb for

  • +Product catalogs with highly variable attributes
  • +Content management and user-generated content
  • +Mobile and web backends that evolve their schema weekly
  • +IoT and event data with time-series collections

best at · OLTP, Content, Metadata

Azure Cosmos DBMicrosoft's globally distributed, multi-API NoSQL and vector database with SLA-backed latency.
MongoDBThe default document database: flexible BSON documents, rich queries and built-in sharding.
overview
Primary model
Document
Document
Also supports
Key-Value, Graph, Wide-Column, Vector, Search Engine
Search Engine, Vector, Time-Series, Spatial
Type
Managed service
Database engine
Status
Active
Active
Developer
Microsoft
MongoDB, Inc.
First release
2017
2009
Latest version
–
9.0.4 (Oct 14, 2026)
License
ProprietaryProprietary Azure service
Source-availableServer Side Public License v1 (Community); commercial (Enterprise)
Free tier
✓
✓
popularity
WhichDB Score
45.3
80.5
Rank
#39
#4
GitHub stars
–
28.7K
Stack Overflow questions
7.8K
175.2K
scale & guarantees
Comfortable data size
Massive (Multi-PB)
Large (≤ 1 PB)
Horizontal scaling
Native
Native
Multi-region
Active active
Read replicas
ACID
Limited
Full
Consistency
Tunable, Strong, Causal, Eventual
Tunable, Causal
Schema
Schemaless
Flexible
Architecture
Distributed, Multi primary, Serverless
Primary replica, Distributed, Client server
deployment
Self-hosted
—
✓
Vendor-managed cloud
✓
✓
Serverless
✓
—
Embedded
—
—
Edge
—
—
Clouds
Azure
AWS, Google Cloud, Azure
capabilities
Transactions
✓
✓
Joins
—
✓
Secondary indexes
✓
✓
Full-text search
✓
✓
Vector search
✓
✓
Geospatial
✓
✓
JSON
✓
✓
Change data capture
✓
✓
Triggers
✓
—
Stored procedures
✓
—
Materialized views
—
✓
TTL / expiry
✓
✓
Pub/Sub
—
—
Columnar storage
✓
—
In-memory
—
✓
Durable persistence
✓
✓
Compression
—
✓
Encryption at rest
✓
✓
Role-based access
✓
✓
Time travel
—
—
Branching
—
—
Online schema changes
✓
✓
Streaming ingest
—
—
Offline sync
—
—
Runs in WebAssembly
—
—
interfaces
Query languages
Cosmos DB NoSQL (SQL dialect), MongoDB Query API, CQL, Gremlin
MongoDB Query API (MQL), Aggregation pipeline
Client languages
C#, Java, JavaScript, Python, Go, Rust
C, C++, C#, Go, Java, Kotlin, JavaScript, PHP
Best for
OLTP, IoT, Sessions, Vector search
OLTP, Content, Metadata, IoT
Add more to this comparisonNot sure either fits? Try smart match

Azure Cosmos DB vs MongoDB: FAQ

What is the difference between Azure Cosmos DB and MongoDB?

Azure Cosmos DB: Microsoft's globally distributed, multi-API NoSQL and vector database with SLA-backed latency. MongoDB: The default document database: flexible BSON documents, rich queries and built-in sharding. Licensing: Azure Cosmos DB is proprietary (Proprietary Azure service); MongoDB is source-available (Server Side Public License v1 (Community); commercial (Enterprise)). Azure Cosmos DB is built for larger datasets (Multi-PB) than MongoDB (≤ 1 PB). Transactions: Azure Cosmos DB offers limited ACID; MongoDB offers full.

When should I choose Azure Cosmos DB over MongoDB?

Choose Azure Cosmos DB for globally distributed user and session data; IoT telemetry and device state; and chat history and memory for AI agents. Choose MongoDB for product catalogs with highly variable attributes; content management and user-generated content; and mobile and web backends that evolve their schema weekly.

Is Azure Cosmos DB or MongoDB more popular?

MongoDB ranks #4 on the WhichDB Score (80.5/100) and Azure Cosmos DB ranks #39 (45.3/100). Popularity is not fit: check the requirements that matter for your project.

Are Azure Cosmos DB and MongoDB open source?

No. Azure Cosmos DB is proprietary, closed-source software. Not in the OSI sense. MongoDB is source-available: you can read the code, but the license restricts some uses, typically offering it as a competing managed service. License: Server Side Public License v1 (Community); commercial (Enterprise).