MongoDB is a serverless, distributed database orientated towards documents, in other words, saving data in BSON documents instead of registries, making it much more expressive and powerful. It's got all the advantages and usages of a relational database, but being more flexible and dynamic.

The MondoDB Atlas is a database on a global cloud created with modern applications in mind, and it's distributed and safe by default, alongside being managed in AWS, Google Cloud and Azure.

Amazon DynamoDB is a key-value and document database that delivers single-digit millisecond performance at any scale. It's a fully managed, multi-region, multi-active, durable database with built-in security, backup and restore, and in-memory caching for internet-scale applications.

DynamoDB differs from other Amazon services by allowing developers to purchase a service based on throughput, rather than storage. If Auto Scaling is enabled, then the database will scale automatically. Additionally, administrators can request throughput changes and DynamoDB will spread the data and traffic over a number of servers using solid-state drives, allowing predictable performance.

Plans

• Shared: Free forever with a M0 cluster, with a 512MB storage capacity, and shared RAM. Also has M2 and M5 versions available with a monthly fee of $9 and $25 respectively. Great for learning and exploring about MongoDB.
  
• Serverless: For serverless applications with a variable traffic that's generally on the lower values. It requires a minimal amount of configuration. Has a free of $0.30 per read, and has extra frees according to the operations you do.
• Dedicated: For production applications that have a sophisticated workload requirement, has advanced configuration controls, with cluster prices ranging from $0.08 to to $33.26/hr.

Example Pricing

Applications with 10M reads ($2.75), 1M writes ($1.25), 1GB storage ($0.25) and 1GB data transfer ($0.015-0.10 according to traffic): $4.3 USD tops.

Dynamo DB's prices vary according to region, the provided example utilizes the US East (N. Virginia) prices.

Free Tier

• 25 GB of data storage
  
• 2.5 million stream read requests from DynamoDB Streams
• 1 GB of data transfer out, aggregated across AWS services  
  
  

Example Pricing

Applications with 10M reads ($2,5), 1M writes ($1,25), 1 GB ($0,25) and continuous backup ($0,20) $4,20 USD

Onboarding

Great documentation to start off quickly, with a free plan that's very quick to access. Has a wide amount of resources and guides to learn about it.

Scalability

Automatic, and scalable both horizontally (sharding) and vertically.

Regions​

MongoDB Atlas supports  the following regions: Americas, Asia Pacific, Europe, Middle East and Africa. The choice of cloud provider and region affects network latency for clients accessing your database deployment and the cost of running the database deployment. For clusters, this choice also affects the configuration options for the available cluster tiers. The region refers to the physical location of your MongoDB database deployment.

Backup

​MongoDB Atlas, the official MongoDB cloud service, provides 2 fully-managed methods for backups:

• ​Continuous Backups, which take incremental backups of data in your cluster, ensuring your backups are typically just a few seconds behind the operational system. Atlas continuous backups allow you to restore from stored snapshots or from a selected point in time within the last 24 hours. You can also query a continuous backup snapshot.
• Cloud Provider Snapshots, which provide localized backup storage using the native snapshot functionality of the cluster's cloud service provider.

Security

​MongoDB provides various features, such as authentication, access control, encryption, to secure your MongoDB deployments. Some key security features include: Authentication, SCRAM, Role-Based Access Control, Transport Encryption, among others.

Onboarding
Rich in documentation, with a great tutorial to start things off.

Scalability
Has automatic scaling as an option.

Regions
United States, Africa, Asia Pacific, Europe, Middle East.

To connect programmatically to an AWS service, you use an endpoint. In addition to the standard AWS endpoints, some AWS services offer FIPS endpoints in selected Regions.

Backups 
Charged separatedly from the project. Has three different options: Continuous backups, on-demand, or restoring a table.

Security
AWS is responsible for protecting the infrastructure that runs AWS services in the AWS Cloud. Includes data protection, identity and access management, infrastructure security, and more.

MongoDB is a document database with the scalability and flexibility that you want with the querying and indexing that you need. MongoDB’s document model is simple for developers to learn and use, while still providing all the capabilities needed to meet the most complex requirements at any scale. 

• Rich on JSON Documents
• Allows arrays and nested items as values
• Rich and expressive consulting language
• Filter and order on any field, regardless of the way it's inserted in the document
• Full ACID transactions
• Allows for combinations on inquiries
• Completely automatized
• Security Copy
• Global Clusters

Amazon DynamoDB is a NoSQL database that supports key-value and document data models. Developers can use DynamoDB to build modern, serverless applications that can start small and scale globally to support petabytes of data and tens of millions of read and write requests per second.

• Microsecond latency with DynamoDB Accelerator
  
• Automated global replication with global tables
  
• Read/write capacity modes
  
• On-demand mode
  
• ACID transactions
• Encryption at rest
  
• Point-in-time recovery
  
• On-demand backup and restore
  

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