From their site: Use the Viewer API (available now), Editor API (in closed beta), and Converter API (in closed beta). You will be able to add, to your website or blog, all the MS Office document view, edit and conversion functionalities available on ThinkFree online: Write (for word processing documents), Calc (for spreadsheets), and Show (for presentations).
The following is a list of SDKs from our SDK directory that matched your search term. Though your definition of an SDK may differ, in our world, we define SDKs as platform- specific tools for consuming existing APIs of the sort we list in our API directory. For example, the Ruby SDK for consuming the Twitter Ads API. If you think an SDK, API, or other asset is missing from our directory, be sure to check our guidelines for making contributions to ProgrammableWeb.