Comparing Amazon DocumentDB and MongoDB

What is DocumentDB?

Amazon DocumentDB is a NoSQL JSON document database service with a limited degree of compatibility with MongoDB.

DocumentDB is not based on the MongoDB server and runs no MongoDB code. Rather it emulates the MongoDB API, and runs on top of Amazon’s proprietary back-end platform. This creates significant architectural constraints, functionality limitations, and broken compatibility.

It is supported only on AWS and limited to up to 64TB of storage per cluster. The instance sizes start only from 4GB RAM and 2 CPUs.

What is MongoDB Atlas?

MongoDB offers the fully managed, on-demand, and global MongoDB Atlas service, in a public cloud of your choice. Atlas enables customers to deploy, operate, and scale MongoDB databases on AWS, Azure, Google Cloud, or any combination of those three. MongoDB Atlas is available through a pay-as-you-go model and billed on an hourly basis. It’s easy to get started—use a simple GUI or programmatic API calls to select the public cloud provider, region, instance size, and features you need. MongoDB Atlas provides:

Automated database and infrastructure provisioning, enabling users to take advantage of the latest MongoDB features (including auto-scaling and sharding for scale-out).
Security features for data protection, through network isolation, fine-grained access control, auditing, end-to-end encryption, and more.
Global clusters for a fully managed, globally distributed database that provides low latency, responsive reads and writes to users anywhere, with strong data placement controls for regulatory compliance.
Combined transactional and analytical capabilities with Atlas Analytics Nodes to isolate analytics queries from operational workloads.
Fully integrated native MongoDB data visualization tools via MongoDB Charts.
Fully integrated MongoDB Atlas Data Lake which allows you to quickly and easily query data in any format on Amazon S3 using the MongoDB Query Language (MQL) and tools, unlocking value from your data faster.
Fully managed backups with point in time recovery to protect against data corruption, and the ability to query backups in-place without full restores.
Fine-grained monitoring and customizable alerts for comprehensive performance visibility.
Access to the MongoDB Realm mobile application development platform, with Data Access Controls, Functions, Offline Sync, and Triggers delivered in a completely serverless model.
The Atlas Search service, which provides rich search capabilities against your fully managed databases with no additional infrastructure or systems to provision, manage, or scale.
Live migration to move your self-managed MongoDB clusters into the Atlas service.
Versioned API to make upgrades risk-free, future-proofing your development and deployment.
Widespread coverage on the major cloud platforms with availability in about 80 cloud regions across Amazon Web Services, Microsoft Azure, and Google Cloud. without compromising critical functionality or risking lock-in. This includes multi-cloud clusters, with workloads distributed across providers.

Built and run by the same team that develops the MongoDB Database, MongoDB Atlas is the best way to run MongoDB apps.

Differences Between DocumentDB and MongoDB

The following high-level diagram compares a potential application stack using DocumentDB or MongoDB as their Data-as-a-Service tier.

High level visual description of the DocumentDB and MongoDB Atlas architectures

The key differences between DocumentDB and MongoDB’s on-demand, elastic, and fully managed Atlas service are summarized below.

	Amazon DocumentDB	MongoDB Atlas
Fully compatible with MongoDB	No, incomplete Imitation API fails 70% of correctness tests	Yes
Support for latest MongoDB version	No Feature set resembles MongoDB 3.0/3.2, released in 2015.	Yes MongoDB 5.2
Free Tier Support	Yes, limited 30 day free trial period	Yes Storage: 512 MB, RAM: Variable A free tier cluster never expires.
Pause and Resume Clusters	Yes	Yes
Scale writes and partition data beyond a single node / Sharding support	No No sharding, single primary only. Largest instance supports 30,000 concurrent connections.	Yes Largest Atlas instance supports 128,000 concurrent connections. Full sharding support.
Replicate and scale beyond a single region / Comply with data locality regulations and survive regional outages	Yes, limited Single primary constrained to a single region, with up to 16 cross-region replicas	Yes Global clusters, with up to 50 replicas per shard across multiple regions
High resilience, rapid failure recovery, fast failover, retryable writes, multi-region	No Up to 120-second failover, no retryable writes, no multi-region in a single cluster	Yes Typical failover of 5 seconds, failed reads and writes auto-retried, cluster distributed across multiple regions, including across multiple cloud providers
Multi-statement distributed ACID transactions	Limited Ambiguous commits, poor error handling, small data sizes. Transactions across shards are not available as DocumentDB does not support sharding	Yes
Integrated text search, geospatial processing, graph traversals	No Data must be replicated to multiple adjacent AWS services, driving up cost and complexity	Yes All available from a single API and platform
Hedged Reads Queries submitted to multiple replicas for consistent low latency	No	Yes
Online Archive Automatically tier data out from database to cloud object storage (Amazon S3)	No	Yes Online Archive
Integrated querying of data in Amazon S3	No Data must be replicated to multiple adjacent AWS services, driving up cost and complexity	Yes Atlas Data Lake
On-demand Materialized Views	No	Yes $merge aggregation stage
Schema governance	No Schema controls must be enforced in the app	Yes JSON schema
Rich data types	Limited With no decimal data type, DocumentDB lacks support for lossless processing of complex numeric data	Yes
Reactive, event-driven data pipelines	Limited Change streams run against primary only and incur additional cost.	Yes MongoDB Change Streams and Realm Triggers
Support for role-based access control and authentication restrictions	Limited Coarse-grained roles only	Yes
Client-side field level encryption for fine-grained separation of duties in the cloud	No	Yes
Availability of advanced developer and analysis tools	No	Yes MongoDB Compass, Charts, BI Connector, Spark Connector
Fine-grained monitoring telemetry and prescriptive performance recommendations	No <50 metrics	Yes More than 100 metrics. Performance Advisor for index and schema recommendations
Freedom from vendor lock-in	No AWS only	Yes AWS, Azure, and Google Cloud. Fully-managed, on-demand service available on ~80 regions
Develop and run anywhere On your mobile device, on your laptop, in your own data center, and in hybrid configurations	No AWS only	Yes MongoDB Realm / MongoDB Server / multi-cloud clusters in Atlas
Mobile and Edge Sync	No Data must be replicated to multiple adjacent AWS services, driving up cost and complexity	Yes MongoDB Realm
Access to MongoDB expertise	No	Yes Hundreds of engineers with multi-year MongoDB development, support, and consulting experience.

Amazon DocumentDB
Fully compatible with MongoDB	No, incomplete Imitation API fails 70% of correctness tests
Support for latest MongoDB version	No Feature set resembles MongoDB 3.0/3.2, released in 2015.
Free Tier Support	Yes, limited 30 day free trial period
Pause and Resume Clusters	Yes
Scale writes and partition data beyond a single node / Sharding support	No No sharding, single primary only. Largest instance supports 30,000 concurrent connections.
Replicate and scale beyond a single region / Comply with data locality regulations and survive regional outages	Yes, limited Single primary constrained to a single region, with up to 16 cross-region replicas
High resilience, rapid failure recovery, fast failover, retryable writes, multi-region	No Up to 120-second failover, no retryable writes, no multi-region in a single cluster
Multi-statement distributed ACID transactions	Limited Ambiguous commits, poor error handling, small data sizes. Transactions across shards are not available as DocumentDB does not support sharding
Integrated text search, geospatial processing, graph traversals	No Data must be replicated to multiple adjacent AWS services, driving up cost and complexity
Hedged Reads Queries submitted to multiple replicas for consistent low latency	No
Online Archive Automatically tier data out from database to cloud object storage (Amazon S3)	No
Integrated querying of data in Amazon S3	No Data must be replicated to multiple adjacent AWS services, driving up cost and complexity
On-demand Materialized Views	No
Schema governance	No Schema controls must be enforced in the app
Rich data types	Limited With no decimal data type, DocumentDB lacks support for lossless processing of complex numeric data
Reactive, event-driven data pipelines	Limited Change streams run against primary only and incur additional cost.
Support for role-based access control and authentication restrictions	Limited Coarse-grained roles only
Client-side field level encryption for fine-grained separation of duties in the cloud	No
Availability of advanced developer and analysis tools	No
Fine-grained monitoring telemetry and prescriptive performance recommendations	No <50 metrics
Freedom from vendor lock-in	No AWS only
Develop and run anywhere On your mobile device, on your laptop, in your own data center, and in hybrid configurations	No AWS only
Mobile and Edge Sync	No Data must be replicated to multiple adjacent AWS services, driving up cost and complexity
Access to MongoDB expertise	No

MongoDB Atlas
Fully compatible with MongoDB	Yes
Support for latest MongoDB version	Yes MongoDB 5.2
Free Tier Support	Yes Storage: 512 MB, RAM: Variable A free tier cluster never expires.
Pause and Resume Clusters	Yes
Scale writes and partition data beyond a single node / Sharding support	Yes Largest Atlas instance supports 128,000 concurrent connections. Full sharding support.
Replicate and scale beyond a single region / Comply with data locality regulations and survive regional outages	Yes Global clusters, with up to 50 replicas per shard across multiple regions
High resilience, rapid failure recovery, fast failover, retryable writes, multi-region	Yes Typical failover of 5 seconds, failed reads and writes auto-retried, cluster distributed across multiple regions, including across multiple cloud providers
Multi-statement distributed ACID transactions	Yes
Integrated text search, geospatial processing, graph traversals	Yes All available from a single API and platform
Hedged Reads Queries submitted to multiple replicas for consistent low latency	Yes
Online Archive Automatically tier data out from database to cloud object storage (Amazon S3)	Yes Online Archive
Integrated querying of data in Amazon S3	Yes Atlas Data Lake
On-demand Materialized Views	Yes $merge aggregation stage
Schema governance	Yes JSON schema
Rich data types	Yes
Reactive, event-driven data pipelines	Yes MongoDB Change Streams and Realm Triggers
Support for role-based access control and authentication restrictions	Yes
Client-side field level encryption for fine-grained separation of duties in the cloud	Yes
Availability of advanced developer and analysis tools	Yes MongoDB Compass, Charts, BI Connector, Spark Connector
Fine-grained monitoring telemetry and prescriptive performance recommendations	Yes More than 100 metrics. Performance Advisor for index and schema recommendations
Freedom from vendor lock-in	Yes AWS, Azure, and Google Cloud. Fully-managed, on-demand service available on ~80 regions
Develop and run anywhere On your mobile device, on your laptop, in your own data center, and in hybrid configurations	Yes MongoDB Realm / MongoDB Server / multi-cloud clusters in Atlas
Mobile and Edge Sync	Yes MongoDB Realm
Access to MongoDB expertise	Yes Hundreds of engineers with multi-year MongoDB development, support, and consulting experience.

For additional MongoDB Atlas comparison information, please refer to the following section.

Is DocumentDB Compatible with MongoDB?

DocumentDB claims to support the MongoDB 4.0 API, which implies that it is at parity with MongoDB v4.0, released back in June 2018. In actual fact, the DocumentDB 4.0 feature set still closely resembles early MongoDB 3.0 and 3.2, released in 2015, and compatibility testing reveals it fails 66% of the MongoDB API correctness tests. Applications written for MongoDB will need to be rewritten to work with Amazon DocumentDB. However, since DocumentDB emulates a MongoDB API, applications written for DocumentDB can be easily migrated into MongoDB Atlas.

Interested in migrating from DocumentDB to MongoDB Atlas? Please refer to our migration guide.

Interested in up-to-date results on DocumentDB's compatibility with the MongoDB API? Get the latest results at Is DocumentDB Really MongoDB?

Try MongoDB Atlas for free for a real MongoDB experience.

FAQs

Is DocumentDB really MongoDB?

No. DocumentDB is an Amazon database service with a partially compatible emulation of an old MongoDB API.

For more on this, check out https://isdocumentdbreallymongodb.com.

What is the difference between MongoDB and DocumentDB?

There are a large number of key differences and advantages to MongoDB Atlas over DocumentDB. Those are listed in the table above.

Does Amazon’s DocumentDB use MongoDB?

DocumentDB is not based on the MongoDB server and runs no MongoDB code.

Which database is DocumentDB based on?

DocumentDB is based on Amazon’s Aurora backend platform.

Is MongoDB Atlas free?

MongoDB Atlas offers a free cluster tier which never expires, giving you the ability to try out the database for your application as long as you wish. Amazon DocumentDB offers a limited free trial period which will expire after 30 days.

Is DocumentDB a relational database?

No. DocumentDB is a NoSQL document database.