Is it possible to create and edit an excel document using OpenXML SDK without creating a local file?
As per the documentation the Create method demands
Adding another answer as I spent way too much time searching for this: Another way to save a SpreadsheetDocument to a stream is by calling SpreadsheetDocument.Clone(Stream s)
It has the benefit of letting you save to a stream even if you created the document from a file or a stream you don't want to save to.