FerretDB (formerly MangoDB) is an open-source proxy, which converts MongoDB wire protocol queries to SQL, and uses PostgreSQL as a database engine.
Cost / License
- Free
- Open Source (Apache-2.0)
Platforms
- Mac
- Windows
- Linux
- Online
- Self-Hosted
H2 Database Engine is described as 'H2 is a relational database management system written in Java. It can be embedded in Java applications or run in the client-server mode. The disk footprint (size of the jar file) is about 1 MB' and is a relational database in the development category. There are more than 50 alternatives to H2 Database Engine for a variety of platforms, including Windows, Linux, Mac, Web-based and BSD apps. The best H2 Database Engine alternative is SQLite, which is both free and Open Source. Other great apps like H2 Database Engine are PostgreSQL, MySQL Community Edition, MariaDB and MongoDB.
FerretDB (formerly MangoDB) is an open-source proxy, which converts MongoDB wire protocol queries to SQL, and uses PostgreSQL as a database engine.
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.

YDB is an open source Distributed SQL Database that combines high availability and scalability with strong consistency and ACID transactions.
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.
Amazon Redshift uses SQL to analyze structured and semi-structured data across data warehouses, operational databases, and data lakes, using AWS-designed hardware and machine learning to deliver the best price performance at any scale.


Oracle Database delivers industry leading performance, scalability, security and reliability on a choice of clustered or single-servers running Windows, Linux, and UNIX. It provides comprehensive features to easily manage the most demanding transaction processing, business...

An embedded database built on object storage. Unlike traditional LSM-tree storage engines, SlateDB writes data to object storage to provide bottomless storage capacity, high durability, and easy replication.


Titan is a scalable graph database optimized for storing and querying graphs containing hundreds of billions of vertices and edges distributed across a multi-machine cluster. Titan is a transactional database that can support thousands of concurrent users executing complex graph...




HSQLDB (Hyper Structured Query Language Database) is a relational database management system written in Java. It has a JDBC driver and supports a large subset of SQL-92 and SQL:2008 standards. It offers a fast, small (around 1300 kilobytes in version 2.

CUBRID is a comprehensive GPL/BSD open source relational database management system highly optimized for Web Applications. CUBRID is being developed in C/C++. Includes native HA, online hot backup, and other features. JDBC, PHP, ODBC/.NET, Ruby & Python APIs.