Android Apps to 2 Way Sync

Google Sync was a free service offered by Google to synchronize mail, contacts, and calendar data across multiple devices and platforms. It leveraged various protocols like Exchange ActiveSync, CardDAV, and CalDAV to push updates in real-time, ensuring users had consistent information wherever they accessed it.

FolderSync is a robust synchronization and backup tool for Android, facilitating effortless file transfers between your local storage and a multitude of cloud services. It offers a comprehensive set of features for automating syncing tasks, managing files, and ensuring data security.

git-annex is a powerful, distributed file synchronization system designed for managing large files and datasets within a Git-like framework.

Insync is a powerful desktop client for various cloud storage services, including Google Drive, Dropbox, OneDrive, and more. It offers features like multi-account support, selective sync, network drive mapping, and robust backup capabilities for users looking to integrate their cloud storage seamlessly with their desktop environment.

Syncplicity is a robust file synchronization and sharing platform designed for businesses, offering secure cloud storage, collaborative tools, and granular control over data.