Maximum number of databases?

The offical documention of DocumentDB does not have any limitations related to the maximum amount of allowed databases per cluster. PostgreSQL (which runs under the hood of DocumentDB) also has no limitation. Just keep in mind - that creating a massive amount of databases can negatively effect your whole cluster (open files, indicies, open connections, etc.).

Thank you!

DocumentDB has a limit of 100,000 databases per cluster . Refer to following documentation for more details : https://docs.aws.amazon.com/documentdb/latest/developerguide/limits.html#limits-cluster