For heylogin, a smartphone is strongly required for technical reasons, as we use the built-in security element for encryption instead of a master password. Thus, heylogin supports smartphone usage, but limited to one device per user. This also means that you cannot log out of the mobile app to log in with another account.
Otherwise, we are largely device-independent. heylogin must be connected to a device's browser and the plugin must be installed. This can be done on as many desktop PCs as desired.
The exception: We do not officially support tablets. Tablet support is planned for the future, but until that happens, you may encounter unexpected problems when using a tablet.