an embeddable spreadsheet for your web application
...The user interface is written entirely in JavaScript and its server-side API is pure Java based on the OpenXLS spreadsheet engine. Neither the client nor the server needs Excel or any browser plugins.
Sheetster is primarily intended for developers who want to integrate spreadsheets into their web applications. Towards that end it provides a server-side API for document storage connectors and a rich REST API for manipulating open spreadsheets. It can also be deployed stand-alone by a website administrator to provide spreadsheet editing with a rudimentary CMS.