Open Source PostgreSQL Alternatives

MariaDB is an free and open-source, community-developed relational database management system. MariaDB is a fork of MySQL, and is developed and maintained by the creators of MySQL, after concerns over its acquisition by Oracle Corporation in 2009. The databases comes bundled by default with most Linux distributions and is also apart of most cloud offerings. MariaDB is built upon the values of performance, stability, and openness which is ensured through the MariaDB Foundation.

SQLite is a free and open-source relational database management system that implements a small, fast, self-contained, high-reliability, full-featured, SQL database engine. Rather than being a typical client–server database engine, SQLite is self-contained and can be embedded into applications. Making it perfect for development frameworks that want to provide a default database without setup, or applications that needs an embedded database. SQLite is built into all mobile operating systems and most computers and comes bundled with a countless applications. SQLite is also ACID-compliant and implements most of the SQL standard, generally following PostgreSQL syntax.

MonetDB is an column-oriented database management system developed at the Centrum Wiskunde & Informatica. The database is released as free and open source software under the Mozilla Public License 2.0. By design, MonetDB can handle high performance on complex queries against large databases with hundreds of columns and millions of rows.

PouchDB is a free and open-source JavaScript database inspired by Apache CouchDB. The database is designed from the ground-up to run well within modern web browsers. With PouchDB you can create web applications that works as well offline as they do online. PouchDB achives this by storing data locally, then synchronize it with CouchDB and compatible servers when the user get internet access once again. This is especially useful for applications facing countries and regions with lower quality internet connections or unstable infrastructure.

QuestDB is a relational column-oriented time series database designed for real-time analytics on time series and event data. It uses the SQL language and include extensions for time series data. QuestDB is released as free and open source software and distributed as a single binary including a trimmed version of the JVM (Java Virtual Machine) weighing in at only 24.5 MB.

TimescaleDB is a leading open-source relational database for time-series data. The database is provided as fully managed or self‑hosted software, giving the power of choice back to developers and organizations. Timescale gives you all the reliability and flexibility of PostgreSQL. It allows you to use regular SQL to construct queries to better understand your products and your users. While achieve 10-100x faster queries than PostgreSQL, InfluxDB, and MongoDB with native optimizations for time-series.

Cockroach is a distributed key/value datastore that allow you to build, scale and manage modern, data-intensive applications. The database delivers distributed SQL by combining the familiarity of relational data with limitless, elastic cloud scale and bulletproof resilience. Correct data is a must for mission-critical and even the most common applications. CockroachDB provides guaranteed ACID compliant transactions, allowing you to fully trust your data.

VoltDB is a blazingly fast NewSQL database management system that is specifically designed to run on modern scale-out architectures - fast, inexpensive servers connected via high-speed data networks. VoltDB is a popular choice for companies with high data throughput requirements, like in the telecommunications industry. 5G has changed the game for telcos, and new rules call for a new way of managing data. VoltDB is built for today’s massive data volume and complexity, allowing businesses to survive and thrive in the age of 5G, IoT, and whatever comes next.

RxDB is short for Reactive Database and is a NoSQL-database for JavaScript Applications like Websites, hybrid Apps, Electron-Apps, Progressive Web Apps and NodeJs. Reactive means that you can not only query the current state, but subscribe to all state changes like the result of a query or even a single field of a document. This is great for UI-based realtime applications in way that makes it easy to develop and also has great performance benefits. To replicate data between your clients and server, RxDB provides modules for realtime replication with any CouchDB compliant endpoint and also with custom GraphQL endpoints.

CrateDB is the leading, distributed SQL database for relational and time‑series data. CrateDB provides a distributed SQL DBMS built atop NoSQL storage & indexing delivers the best of SQL & NoSQL in one DB. It's designed for simple scalability with a masterless architecture with auto-sharding & replication. It also provides solutions for dynamic schema where the schema evolves automatically as new columns are inserted, while handling any tabular or non-tabular data to support a wide range of use cases. CrateDB is the perfect choice for your machine data.

CouchDB is a free and open-source document-oriented NoSQL database developed by the Apache Foundation. The database is written and implemented in the language Erlang and provides the use of multiple formats and protocols to store, transfer, and process data. With CouchDB you query data with JavaScript using MapReduce, and HTTP for an API. Which can be done across multiple distributed CouchDB instances as the database has the ability to synchronize multiple copies of the same database, across servers.

OrientDB is an open-source NoSQL database management system written in Java. The multi-model database supports graph, document, key/value, and object models, where relationships are managed as in graph databases with direct connections between records. The database is extremly efficient and can store over 220,000 records per second on common hardware, and traverse thousands of records in milisecons. OrientDB scales well on multiple machines, thanks to the multi-master replication where there is no single bottleneck on writes like with master-slave replication.