Well, KeePass is self-hosted, and I hadn't heard of strongbox before, but it says on the website:
> Store your data anywhere you like, online or offline. Sync with every major cloud storage provider or your own server over WebDAV or SFTP. Use your Strongbox database with any KeePass compatible client on any platform.
> Store your data anywhere you like, online or offline. Sync with every major cloud storage provider or your own server over WebDAV or SFTP. Use your Strongbox database with any KeePass compatible client on any platform.