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 libraries from ProgrammableWeb's Library Directory that matched your search term. Although there many different interpretations of the word "library" among software developers, ProgrammableWeb adheres to a specific definition so as to clearly distinguish libraries from SDKs and frameworks in a way that will facilitate clean search results. In ProgrammableWeb's parlance, the term "library" is strictly used to describe a platform-specific software tool that, when installed, results in the provisioning a specific API. Conversely, SDKs are exclusively for consuming APIs and Frameworks are agnostic to specific APIs. If you think a library, SDK, API, or other asset is missing from our directory, be sure to check our guidelines for making contributions to ProgrammableWeb.