Where are snippets saved?

The snippets are saved in the “chrome.storage.sync.” This data gets synchronized across all the user’s instances of Chrome where the extension is installed.

How can snippets be synced across all devices?

To sync Gmail snippets from cloudHQ across all devices, enable the sync option for extensions in Google Chrome browser settings. This will automatically install and synchronize the snippets on all your devices as explained in the article on how to ensure that all my snippets are on all devices.