**Note:** It is technically possible to _switch off online mode_ (and allow synced mode only) by running the SilverBullet server with the `--sync-only` flag (or setting the `SB_SYNC_ONLY` environment variable to something). With this flag on, the sync button will not appear in the UI.
In online mode, all content in your space is kept on the server, and a lot of the heavy lifting (such as indexing of pages) happens on the server as well. Content will only be loaded to the client on-demand.
* **Keeps content on the server**: this mode does not synchronize all your content to your client (browser), making this a better fit for large spaces or for cases where you only need to quickly login to SilverBullet to check something, e.g. on a device you don’t usually use. This use case is the reason why this is the default mode.
In this mode, all content is synchronized to the client, and all processing happens there. The server effectively acts as a “dumb data store.” All SilverBullet functionality is available even when there is no network connection available.
* **100% offline capable**: disconnect your client from the network, shutdown the server, and everything still works. Changes synchronize automatically once a network connection is re-established.