Realm is an open-source object database management system, initially for mobile (Android/iOS), also available for platforms such as Xamarin or React Native, and others, including desktop applications (Windows), and is licensed under the Apache License.

In 2016 September, the Realm Mobile Platform was announced, followed by the first stable release in January 2017. It allows two-way synchronization between the Realm Object Server and the client-side databases that belong to the given logged-in user. Both a developer and a commercial edition was released, along with a business license for integrating with other database management systems such as PostgreSQL.