content/operate/rc/databases/active-active/develop/_index.md
Developing globally distributed applications can be challenging, as developers have to think about race conditions and complex combinations of events under geo-failovers and cross-region write conflicts. In Redis Cloud, Active-Active databases simplify developing such applications by directly using built-in smarts for handling conflicting writes based on the data type in use. Instead of depending on just simplistic "last-writer-wins" type conflict resolution, geo-distributed Active-Active databases combine techniques defined in CRDT (conflict-free replicated data types) research with Redis types to provide smart and automatic conflict resolution based on the data type's intent.
An Active-Active database is a globally distributed database that spans multiple cloud provider regions. Each Active-Active database can have many Active-Active database instances that come with added smarts for handling globally distributed writes using the proven CRDT approach. CRDT research describes a set of techniques for creating systems that can handle conflicting writes. CRDBs powered by Multi-Master Replication (MMR) provide a straightforward and effective way to replicate your data between regions and simplify development of complex applications that can maintain correctness under geo-failovers and concurrent cross-region writes to the same data.
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Active-Active databases replicate data between multiple Redis Cloud provider regions. Common uses for Active-Active databases include disaster recovery, geographically redundant applications, and keeping data closer to your users' locations. MMR is always multi-directional amongst the regions configured in the Active-Active database. For unidirectional replication, see [Active-Passive replication]({{< relref "/operate/rc/databases/migrate-databases#sync-using-active-passive" >}}).
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[Learn more about synchronization for each supported data type]({{< relref "/operate/rc/databases/active-active/develop/data-types/" >}}) and [how to develop applications]({{< relref "/operate/rc/databases/active-active/develop/develop-for-aa" >}}) with them on Redis Cloud.