Free Microsoft SQL Server Alternatives

The worlds most popular free open-source relational database, MySQL is used by 150,000 + companies across the globe. The relational database management system is released and distributed under the GPL license and openly developed by the community. MySQL uses SQL as its query language and is fully integrated and ACID compliant.

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.

IBM DB2 is an enterpise-class relational database management system. IBM DB2 is built for mission critical workloads and provides advanced features like adaptive workload management, time travel query, query federation, in-database AI, row/column access control, auditing, and support for JSON, XML, and geospatial data sets. IBM DB2 is used by fortune-500 companies like Bank of America and JPMorgan Chase.

PostgreSQL, or Postgres for short is a widely popular, free and open-source relational database management system. PostgreSQL is available for all major operating systems including macOS, Linux, Windows, BSD and Solaris. The project has been in active development for over 30 years now, and powers many of the applications you use on a daily basis.

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.

RethinkDB is a scalable, open-source database designed for real-time applications. When your app polls your database for data, it becomes slow, unscalable, and cumbersome to maintain. RethinkDB solves this by providing a new database access model, where developers can instruct the database to continuously push updated query results to their applications, without polling.

HSQLDB is a relational database engine written in Java, with a JDBC driver, conforming to ANSI SQL:2016. It's the best for Java developers for development, testing and deployment of database applications. HSQLDB provides a small, fast, multithreaded engine and server with memory and disk tables, LOBs, transaction isolation, multiversion concurrency and ACID.

MemSQL is a free and open-source all-in-one relation database management system. The database lends itself for operational analytics and AI/ML-powered applications that requires fast data ingest, high performance queries and elastic scaling. MemSQL supports ANSI SQL and blended workloads, commonly referred to as translytical, HTAP, HOAP, and ATP workloads. The developer MemSQL Inc, also provides commercially hosted version of the database called MemSQL Helios, a cloud database-as-a-service.

Couchbase, originally known as Membase is an award-winning, open-source, distributed multi-model NoSQL and document-oriented cloud database. It is designed and optimized for interactive applications and may serve many concurrent users by creating, storing, retrieving, aggregating, manipulating and presenting data. Couchbase delivers unmatched versatility, performance, scalability, and financial value across cloud, on-premises, hybrid, distributed cloud, and edge computing deployments.

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.

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.

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.