MariaDB was created by the original developers of MySQL and is guaranteed to stay open source under GPLv2, while MySQL is developed, distributed and supported by Oracle with free and paid editions. For years MariaDB was a drop-in replacement for MySQL, but its own docs say that was only true up to version 5.5; since then, moving from MySQL is usually still easy, with binary compatible data files and client protocol. Pick MariaDB for community governance and extra storage engines, and MySQL for Oracle's editions and HeatWave cloud service.
These two share a history, so the differences hide in the details. I read the MariaDB Foundation's about and in-brief pages, MariaDB's compatibility notes and the MySQL 8.4 manual and product pages to pull them out.
MariaDB and MySQL side by side
| MariaDB | MySQL | |
|---|---|---|
| Who's behind it | MariaDB Foundation, made by MySQL's original developers | Oracle Corporation |
| Licence | GPLv2, guaranteed to stay open source | GPL, plus a commercial licence on sale |
| Drop-in replacement | Up to MariaDB 5.5; usually easy to upgrade since | Not applicable |
| Storage engines | InnoDB, Galera cluster, ColumnStore, Mroonga, S3 and more | Not compared on the pages I read |
| Other-database modes | SQL_MODE=ORACLE and SQL_MODE=MSSQL | None mentioned on the pages I read |
| Company alongside it | MariaDB Corporation, separate from the foundation | Oracle sells Enterprise, Standard and Classic editions and HeatWave |
| Notable users | Wikipedia, WordPress.com and Google, per MariaDB | Described as the most popular open source SQL database |
The drop-in myth, straight from MariaDB's docs
The usual shorthand is that MariaDB is a drop-in replacement for MySQL. MariaDB's own compatibility page is more careful: until MariaDB 5.5, its versions functioned as a drop-in replacement for the equivalent MySQL version, with some limitations. From MariaDB 10.0 onwards it's usually still very easy to upgrade from MySQL, because data files are generally binary compatible, file names and paths are the same and the client protocol is binary compatible.
The same docs now list incompatibilities and feature differences between MariaDB's long-term releases, such as 10.11, 11.4 and 11.8, and MySQL 8.0. So if you plan a switch, test your application against the exact versions involved rather than assuming everything carries over.
What MariaDB adds
The MariaDB Foundation describes MariaDB Server as a general purpose open source relational database used for everything from banking to websites. It lets you choose the storage engine best suited to the job, including Galera for a synchronous multi-master cluster, ColumnStore for large-scale analytics, Mroonga for full-text search in Chinese, Japanese and Korean, and an S3 engine. It also includes GIS and JSON features and SQL modes that mimic Oracle and Microsoft SQL Server syntax, which helps when migrating.
If PostgreSQL is also on your shortlist, our MySQL vs PostgreSQL guide covers it.
What MySQL offers
The MySQL manual calls MySQL the most popular open source SQL database management system, developed, distributed and supported by Oracle. The free Community Edition is under the GPL and includes SQL and NoSQL features. Oracle also sells Enterprise, Standard and Classic editions, an NDB Cluster edition, an embedded edition for software makers and MySQL HeatWave, a cloud service for transactions, analytics and machine learning.
For a document database set against a relational one, see our MongoDB vs PostgreSQL guide.
Five questions to settle it
- Do you want a database governed by a foundation rather than one company? MariaDB.
- Do you need Oracle support contracts or HeatWave? MySQL.
- Migrating from Oracle or SQL Server code? Try MariaDB's compatibility SQL modes.
- Need a synchronous multi-master cluster out of the box? Look at MariaDB with Galera.
- Switching an existing MySQL app? Test against MariaDB's compatibility notes for your versions.
If you're planning a move between systems, read my notes on using a database migration service, and keep your setup safe with this explainer on what SQL injection is and how to stop it.
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My advice on MariaDB or MySQL
For a new self-hosted project, I'd lean towards MariaDB for its open source guarantee, foundation governance and extra storage engines. If your host, platform or vendor support contract expects MySQL, stay with MySQL and use Oracle's editions when you need them. And if you're switching from one to the other, treat it as a migration, not a swap: back up, test on the exact versions and read MariaDB's incompatibility list first.
Do you make database tools? Tool makers can ask to be considered for a featured place in comparisons like this one.
Frequently asked questions
Is MariaDB a drop-in replacement for MySQL?
MariaDB's docs say its versions worked as a drop-in replacement up to MariaDB 5.5. Since 10.0, upgrading from MySQL is usually still easy, but there are documented incompatibilities.
Who created MariaDB?
The MariaDB Foundation says MariaDB Server is made by the original developers of MySQL.
Is MariaDB free?
Yes. MariaDB Server is released under GPLv2 and the foundation says it's guaranteed to remain open source.
Who owns MySQL?
MySQL is developed, distributed and supported by Oracle Corporation, according to the MySQL reference manual.
Who uses MariaDB?
The MariaDB Foundation names Wikipedia, WordPress.com and Google among its notable users.
