Support for workbook.worksheets.addFromBase64 in Excel JS for Excel Online

Brass Contributor



I'd like to know about Excel's Product Team the plans to deliver workbook.worksheets.addFromBase64 for Excel Online. Currently, it works only in Excel for Mac and Desktop (it doesn't work for iPad and Excel Online).


I've been developing Office Addins for the last 5 years and it is by far the most important API. Why? Because it is about templates.


This is the flow of all corporate Excel Addins I've developed:

-User opens the Addin and login in Addin Pane.

-User selects a spreadsheet model from its company in the Addin Pane.

-The model loads and then gets poulated via Excel's API from a database.

-User edits then click on save.

-Of course, there is a lot validation to save the data back to database.


This is the flow with all of my corporate customers. I've never had any use of Office Addins for anything different from that. That's why it would be nice this API to work with Excel Online.


We don't want to "recreate the wheel" and use the API recreate a worksheet in Excel Online, it is simply too much work to do.


Don't get me wrong, as it works for both Excel and Mac, I can deliver great experience to 95%+ of my customers. But there is always a customer that signs only Office E1 and its employees use only Excel Online.

3 Replies
Hi Felipe, this API is now generally available for Web, Windows, Mac:, as part of the Excel 1.13 Requirement set!

P.s. If you have any issues, please post them on our github at, or ask questions on stack overflow with the tag [office-js]. We don't typically monitor tech community, so apologies on the delta in getting back to you.
Hi, I just saw your message. This is great news! Thanks for the good work!