Bigtable is a fully managed wide-column and key-value NoSQL database service for large analytical and operational workloads as part of the Google Cloud Platform portfolio.
Cost / License
- Paid
- Proprietary
Platforms
- Online
MongoDB is described as 'Document database with the scalability and flexibility that you want with the querying and indexing that you need' and is a very popular relational database in the development category. There are more than 100 alternatives to MongoDB for a variety of platforms, including Linux, Windows, Mac, Self-Hosted and Web-based apps. The best MongoDB alternative is PostgreSQL, which is both free and Open Source. Other great apps like MongoDB are SQLite, MySQL Community Edition, MariaDB and Redis.
Bigtable is a fully managed wide-column and key-value NoSQL database service for large analytical and operational workloads as part of the Google Cloud Platform portfolio.

Cockroach is a distributed key/value datastore which supports ACID transactional semantics and versioned values as first-class features. The primary design goal is global consistency and survivability, hence the name.

FerretDB (formerly MangoDB) is an open-source proxy, which converts MongoDB wire protocol queries to SQL, and uses PostgreSQL as a database engine.
Couchbase is the NoSQL database market share leader, with production deployments at AOL, Deutsche Post, NTT Docomo, Salesforce.com, Turner Broadcasting Systems, Zynga and hundreds of other organizations worldwide.
DiceDB is an open-source, fast, reactive, in-memory database optimized for modern hardware. Commonly used as a cache, it offers a familiar interface while enabling real-time data updates through query subscriptions.

Amazon DynamoDB is a fully managed NoSQL database service offered by Amazon.com as part of the Amazon Web Services portfolio. It was announced by Amazon CTO Werner Vogels on January 18, 2012.OverviewDynamoDB differs from other Amazon services by allowing developers to purchase a...

A full-stack, syncing database that runs on both server and client. Pluggable storage (indexeddb, sqlite, durable objects), syncs over websockets, and works with your favorite framework (React, Solid, Vue, Svelte).

Valkey is an open source (BSD) high-performance key/value datastore that supports a variety of workloads such as caching, message queues, and can act as a primary database. Valkey can run as either a standalone daemon or in a cluster, with options for replication and high...




Amazon DocumentDB (with MongoDB compatibility) is a fast, reliable, and fully managed database service that makes it easy for you to set up, operate, and scale MongoDB-compatible databases.
is an open-source distributed NoSQL wide-column data store. It is compatible with Apache Cassandra and supports the same protocols (CQL and Thrift) and file formats (SSTable), as well as the Amazon DynamoDB API, and is based on C++20.


I like it because it is tries to build MongoDB in open-source!