MongoDB is the leading NoSQL software. It is open-source and supported by a strong community of users. It can be used unsupported, in the community version, or supported with the enterprise edition. But it is important to keep your version updated with the latest upgrade. As of 2017, it also comes in a hosted version called Atlas, which provides both storage and software in the cloud. MongoDB can be used with a variety of storage solutions — on premises, in the cloud, or hybrid.