ownCloud is described as 'Self-hosted platform for secure file sync, sharing, calendar, and contact management with desktop, mobile, web access, and multi-device syncing' and is a leading Cloud Storage service in the backup & sync category. There are more than 100 alternatives to ownCloud for a variety of platforms, including Web-based, Windows, Mac, Linux and Android apps. The best ownCloud alternative is Nextcloud, which is both free and Open Source. Other great apps like ownCloud are Dropbox, Google Drive, MEGA and Filen.
Offers secure content management with workflow automation, AI-driven insights, 10GB free cloud storage, e-signature support, integration with 1,500+ apps, file-level security, offline access, document commenting, real-time search, and previews for 200+ file types.
ownCloud runs on your own server, not on Box' servers.
Cozy makes the personal cloud more accessible. Respectful of the user's privacy, Cozy simplifies daily tasks: synchronize and backup photos, automate bills downloading, manage expenses, etc. Flexible and easy to use, their Open Source platform allows users to create and...
Cozy Cloud has now joined 
Twake.
with cozy you can sync more than just files. like contacts and calendars which is more important to me than file sharing.
Although tailored for families, it offers many of the same features as a typical groupware solution like OwnCloud -- calendaring, group messaging, sharing of files & content, etc.
IPFS is a global, versioned, peer-to-peer filesystem. It combines ideas from Git, BitTorrent, Kademlia, SFS, and the web. It is like a single bittorrent swarm, exchanging git objects. IPFS provides an interface as simple as the HTTP web, but with permanence built in.
OwnCloud is groupware. IPFS is a file-sync storage solution. Just because they have overlapping functionality, does NOT make them interchangeable.
Pydio is the mature alternative to Dropbox and Box.com, to build your own box, on your own servers.
OwnCloud is groupware. Pydio is a file-sync storage solution. Just because they have overlapping functionality, does NOT make them interchangeable.
Sync-in is a secure, open-source platform for file storage, synchronization, and team collaboration — designed to give organizations full control over their data and workflows, while remaining flexible enough for individual needs.
MediaFire is the simple solution for uploading and downloading files on the internet. It focuses on providing a positive experience for downloaders, but does not offer an affiliate program for uploaders.
SpiderOak provides an easy, secure and consolidated online backup, storage, access, sharing & sync tool for Windows, macOS, and Linux (Ubuntu, Debian & Fedora). SpiderOak offers a different approach to online backup, synchronization, and sharing.
Not user-operated, but a commercial system with a focus on encryption and privacy
Lightweight, self-hosted encrypted cloud storage enabling fast uploads and downloads, easy Docker install, secure public link sharing, browser-side cryptography, searchable metadata, and low RAM footprint. Designed for privacy, performance, and file management.
Icedrive is a cloud storage, backup and file sharing service with browser, desktop and mobile apps.
The Icedrive desktop application allows users to mount their cloud storage space as a real hard drive.
Trustless collaboration platform with decentralized file-sharing, collaborative editing, cheap storage, privacy controls, onchain team and community access, website and blog publishing, open workflows, customizable spaces, and alternatives to traditional online suites.
Lightweight file storage with a Rust backend and optimized binary for efficiency, offering responsive UI on desktop and mobile, simple setup, multilingual English and Spanish support, no PHP dependency, and designed for minimal resource use on home servers.
Open source, self-hosted suite featuring mail, calendar, drive, and contacts. Provides privacy without analytics or ads, file versioning, sharing, recurring calendar events, and compatibility with open standards, keeping control and portability with the user.
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Box allows you to share a chunk of your data by uploading it to THEIR storage space : you do not control it any longer. While ownCloud on the opposite allows you to securely share part of YOUR (Home / Enterprise) server storage space. You stay in control.