Seamless is built on top of SharePoint Online from Office 365 and therefore requires an active SharePoint Online subscription from Office 365. Each person who accesses SharePoint Online must be assigned to an Office 365 plan (E1-E5, K1). SharePoint Online Plan 1 or SharePoint Online Plan 2 standalone service can also be used.
External Seamless users requires an Office 365 Work or School Account or a Microsoft Personal Account (Live-ID) for sign in. Sign-up for a new Live-ID for free under signup.live.com.
For the best user experience, we also recommend licensing and installing Office 365 ProPlus on your PC or Mac.
Under the following links you can find and compare the available price plans: