NextCloud's documentation page offers thorough information for users, admins, and developers as well as links to its forums, IRC channel, and social media pages for community-based support.

A marketplace offers numerous apps to extend its features. Like the other solutions on this list, NextCloud is self-hosted, but if you don't want to roll your own NextCloud server on Linux, the company partners with several providers for setup and hosting and sells servers, appliances, and support. It also encrypts data during transfer and at rest and integrates with mobile device management and authentication mechanisms (including LDAP/AD, single-sign-on, two-factor authentication, etc.). It has HIPAA (healthcare) and GDPR (privacy) compliance features and offers extensive data-policy enforcement, encryption, user management, and auditing capabilities. Nextcloud touts its high security and regulatory compliance as a distinguishing feature. NextCloud spun out of ownCloud in 2016 and shares much of the same functionality. OwnCloud offers comprehensive documentation, including an installation guide and manuals for users, admins, and developers, and you can access its source code in its GitHub repository. You can also expand its functionality with a wide variety of third-party apps available in its marketplace, and there is also a paid, commercially licensed enterprise edition. Data transfers are secured by end-to-end encryption (E2EE) and SSL encryption. With ownCloud, you can sync and access files through clients for Linux, MacOS, or Windows computers or mobile apps for Android and iOS devices, and provide password-protected links to others for collaboration or file upload/download. (Self-hosting is a common thread among the apps on this list.) Its primary difference (aside from its open source license) is that your files are hosted on your private Linux server or cloud, giving users complete control over your data.

Its primary features-file and folding sharing, document collaboration-are similar to Dropbox's. OwnCloud, launched in 2010, is the oldest application on this list, but don't let that fool you: It's still very popular (with over 1.5 million users, according to the company) and actively maintained by a community of 1,100 contributors, with updates released regularly.

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