Open-source Sync.com alternatives

Syncthing is a continuous file synchronization program that keeps files in sync between two or more computers. It is written in Go and released under the MPL-2.0 license, and its peer-to-peer design means your devices exchange files with each other directly rather than through a central storage service.

The project ranks its goals in order of importance: protect users from data loss, stay secure against eavesdropping and tampering, be easy to use, work automatically with minimal interaction, run on every common computer, and focus on empowering individuals. Several graphical front ends exist for Windows, Mac and Linux, and the repository includes sample files for running it as a background service.

Syncthing can also be run in Docker, and a getting-started guide covers setup. It suits individuals and small groups who want to sync folders between laptops, desktops and servers they control instead of relying on a hosted file-sharing service, and who value open, auditable software.

Nextcloud Server is a platform for keeping your files, contacts, calendars and other data on a server of your choosing. Content is synchronized across your devices, can be shared with other people for viewing or collaboration, and stays under your control rather than with a large cloud provider. It grew out of the ownCloud lineage.

Functionality can be expanded through hundreds of apps in its App Store, including Calendar, Contacts, Mail and Video Chat. Security measures include encryption mechanisms, a public bug bounty program and two-factor authentication. There are several ways to get a Nextcloud: sign up with a provider, install the server yourself on your own hardware or with a ready-to-use appliance, buy a device that comes with it preinstalled, or find a service provider to host it for you.

The server is written in PHP and JavaScript under the AGPL-3.0 license. Nextcloud GmbH also offers an Enterprise edition aimed at public sector, education and company users. It suits households, schools and organizations that want to replace commercial cloud storage and office suites with something they run themselves.

Cryptomator encrypts files on your own device before they reach a cloud storage service. It presents an encrypted vault as a virtual drive, so you work with files as if they were on a USB flash drive while only encrypted data is synced. It runs on Windows, macOS and Linux, is written in Java and is released under the GPL-3.0 license.

It works with any cloud service that synchronizes with a local directory, including Dropbox, Google Drive, OneDrive, MEGA, pCloud, ownCloud and Nextcloud. Files are protected with AES encryption using 256-bit keys, file names are encrypted, and the folder structure is obfuscated. You can keep as many vaults as you like, each with its own password.

The security design uses scrypt key derivation and cryptographically secure random numbers, and it wipes sensitive data from memory quickly. Encryption is client-side, so no account is needed and no data is shared with an online service. The project is provided free of charge and relies on donations and sponsors for development.

Seafile is a file synchronization and sharing platform written mainly in C. Beyond keeping folders in sync across devices and sharing them with others, it describes a newer way of organizing files using extensible file properties and flexible views. Topics also tie it to wikis, Markdown, knowledge management and document management.

The project's homepage could not be fetched while preparing this entry, so the details here come from the repository description, its topics and general knowledge of the product. Seafile is known for client apps on desktop and mobile, libraries as the unit of syncing and sharing, and an emphasis on reliable syncing of large numbers of files.

The core server is open source, with its license listed as 'Other' on GitHub, and the vendor also sells a professional edition and offers hosted service. You can run it on your own servers, which suits teams and organizations that want private cloud storage under their control.

Nextcloud All-in-One, often shortened to AIO, is the official installation method for Nextcloud. It provides easy deployment and maintenance, packaging most of what an instance needs into a set of containers that are managed from a simple web interface.

The bundle includes Nextcloud itself, a high-performance backend for Files, Redis and APCu caching, PostgreSQL as the database, and optional components such as Nextcloud Office, Talk with its TURN server, a recording server, ClamAV antivirus, full-text search, a whiteboard, Imaginary for previews, and a backup solution based on BorgBackup. Updates, daily backups and restore from an archive are handled from the AIO interface.

It is designed to work behind existing reverse proxies, Cloudflare Tunnel or Tailscale. The project is written in PHP, licensed under AGPL-3.0, and runs on your own hardware with Docker. The maintainers are actively looking for contributors to help with development.

ownCloud Core is the server component of ownCloud Classic, a self-hosted platform for file storage, synchronization and sharing. It is the foundation on which apps such as Activity, Calendar and Contacts are built, and is written in PHP and JavaScript.

It ships with servers for WebDAV, CalDAV and CardDAV, an app plugin architecture, backends for external storage, support for encryption, user and group management, and a REST API. The server runs on PHP with MySQL, MariaDB, PostgreSQL or SQLite, and is also available as a Docker image on Docker Hub. Its topics point to federated sharing and enterprise use.

ownCloud Classic is licensed under AGPL-3.0, and installation is covered by the official manual. For the next-generation platform, the project points to ownCloud Infinite Scale. Contributors follow a rebase workflow with signed commits and DCO sign-off, and enterprise support is available from the vendor. It suits organizations and individuals who want to keep files on their own servers instead of a public cloud.

Pydio Cells is a file sharing and content collaboration platform for organizations. It is a full rewrite of the earlier Pydio project in the Go language, built around a microservice architecture. Project topics describe it as a file sharing platform and a Go application made of microservices, and it is licensed under AGPL-3.0.

The README covers building from source for development and testing. It requires a recent Go toolchain and a MySQL or MariaDB database. You build the backend, create a database, run the installer, which guides you through setup, and then open the default site on port 8080. The project says it was developed and tested on macOS, Ubuntu, Debian and CentOS, and that Windows may still have unknown issues.

A notice at the top of the README warns that the version 5 branch is a work in progress to be used at your own risk. Tests and a live reload setup based on the air tool are described for contributors, and a contributing guide explains how to add tests. The vendor, Pydio, hosts documentation, a developer guide and an issue tracker.

Sync-in is a self-hosted platform for file storage, synchronization, and team collaboration. It lets you run your own workspace for files, documents, shares, and collaborative work while keeping control of your infrastructure and data. It is designed to stay fast and lightweight, keeping files readable on the filesystem and adding collaboration features only where needed. It is written in TypeScript and released under the AGPL-3.0 license.

The web interface offers drag and drop, a smart clipboard, gallery view, sorting, filtering, and file previews. Authentication supports local accounts, OIDC, LDAP, MFA, recovery codes, and application passwords, and files are organized into spaces and shares. Topics list full-text search, real-time collaborative editing, WebDAV, and a desktop and command-line sync client.

Installation is documented for Docker and for NPM, and a demo is available. The project positions itself as a private cloud alternative to Dropbox and Nextcloud, suiting organizations, homelab users, and teams that want sovereign file sharing.