Webextensions folder not getting included in base64 format of currently opened document.

Question

Webextensions folder not getting included in base64 format of currently opened document.

Rajat Bharadwaj 5

Hi Team,

We are facing issue where as part of requirement we need to convert existing document to base64 that needs to be passed as parameter to our backend API.

We are storing some metadata related to our usecase using Office settings API which is stored in webextension1.xml. (word > webextensions > webextension1.xml )

 Office.context.document.settings.set(key, value);

As part of our requirement we need webextensions folder to be part of base64 which is being created using below Ofice JS API.

We tried below approach using "getFileAsync" but its not helping.

Office.context.document.getFileAsync(
Office.FileType.Compressed )

Can you please help how can we include webextensions folder in base64? Please refer the screenshot

Screenshot 2026-02-27 at 11.44.32 AM.png

2 answers

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Answer 1

Teddie-D 12,845 Microsoft External Staff Moderator

Hi @Rajat Bharadwaj

Thank you for posting your question in the Microsoft Q&A forum.

When using Office.context.document.getFileAsync(Office.FileType.Compressed, …) in Word, the returned DOCX package may sometimes be missing the word/webextensions folder. As a result, any add‑in settings stored via Office.context.document.settings which are persisted into webextension1.xml won’t appear in the Base64 output. This behavior has been reported in Custom settings are not present in files retrieved using getFileAsync() · Issue #6434 · OfficeDev/o…

Currently, there isn’t an Office.js API option to force inclusion of the webextensions folder when the host application omits it. If you depend on those settings, here are some practical workarounds:

1.Trigger a real document save before export

-After a manual save (File > Save), the settings are correctly included in the package.

-The issue report also notes it does not appear in Office on the web, so Word for web may work normally.

2.Send metadata separately from the document

If your backend requires both the document and metadata, consider sending:

-Base64 of the document from getFileAsync.

-A separate JSON payload containing your metadata instead of embedding it in settings.

This avoids dependency on Word’s packaging internals, which can change across versions.

Reference: Persist add-in state and settings - Office Add-ins | Microsoft Learn.

3.Use alternative storage inside the document

Instead of relying on webextensions, metadata can be stored in:

-Custom document properties

-Custom XML parts

-Hidden content controls

These approaches store data in standard OOXML document parts, which are included in the document package generated by Word.

Reference: Office.Document interface - Office Add-ins | Microsoft Learn.

I hope this clarifies the behavior and available options.

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Teddie-D 12,845 Reputation points Microsoft External Staff Moderator

2026-03-01T23:36:10.26+00:00

Hi @Rajat Bharadwaj
May I know if you have got any chance to check my answer? If you need further assistance, please feel free to let me know. Thank you!
Rajat Bharadwaj 5 Reputation points

2026-03-02T05:30:12.64+00:00
Hi @Teddie-D

Thank you for your input, We tried below approach

I tested flow to trigger a real document save before export still word/extensions folder is not included in base64.

Can you help which storage would be ideal for us? Our requirement is to show a tree structure of the document hence we are storing metadata in tree hierarchy array as part of metadata. Since data can be huge based on document size "Custom document properties " is not preferable as it supports maximum 255 character? in that case "Custom XML parts" will be a ideal option?

Also we have a requirement to automatically open addin whenever document is opened hence we were setting "Office.AutoShowTaskpaneWithDocument" property to true. Based on your response and issue mentioned in your comment https://github.com/OfficeDev/office-js/issues/6434
This functionality will be broken ? I see this as a regression, is there any ETA for this fix?

Also based on your response "When using Office.context.document.getFileAsync(Office.FileType.Compressed, …) in Word, the returned DOCX package may sometimes be missing the word/webextensions folder."

You mentioned sometimes it doesn't pick word/webextensions folder but i can see this issue reproducible everytime.

Office.context.document.settings.set("Office.AutoShowTaskpaneWithDocument", true); Office.context.document.settings.saveAsync(function (asyncResult) { if (asyncResult.status !== Office.AsyncResultStatus.Succeeded) { console.log('Settings save failed:', asyncResult.error); } });
Teddie-D 12,845 Reputation points Microsoft External Staff Moderator

2026-03-02T06:28:38.61+00:00

Hi @Rajat Bharadwaj
Since your metadata can be large and hierarchical, Custom XML Parts are the most appropriate storage mechanism. Custom document properties are limited in size and are not suitable for large structured data. Custom XML Parts are stored as standard OOXML document parts and are included in the document package generated by Word.

Regarding Office.AutoShowTaskpaneWithDocument: this functionality depends on the webextension part being present in the physical document. If the document is reconstructed from a Base64 package generated by getFileAsync and that package omits the /word/webextensions folder, the auto-open behavior will not function for that reconstructed file.

At this time, there is no Office.js API to force inclusion of the webextensions folder, and there is no publicly announced ETA for a fix to the reported regression. We recommend monitoring the GitHub issue.
Thank you for your patience and understanding.

Answer 2

Including the webextensions folder (and thus webextension1.xml that stores Office settings) in the base64 produced by Office.js is not supported by the documented APIs in the provided context.

The relevant Word/Office.js objects in the context (such as Word.WebSettings) only expose limited properties and methods related to saving as a webpage (organizeInFolder, folderSuffix, useDefaultFolderSuffix) and do not provide any mechanism to:

Access or serialize the webextensions part of the document package, or
Control what Office.context.document.getFileAsync(Office.FileType.Compressed) includes in the returned file.

Office.context.document.settings is designed as a key/value store for add-ins and is persisted in the document’s web extension part, but the context does not document any API to explicitly include or extract that webextensions folder when exporting the document via Office.js.

Given only the documented APIs in the context, there is no supported way shown to force getFileAsync (or any other Office.js API here) to include the webextensions folder in the base64 payload.

References:

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Webextensions folder not getting included in base64 format of currently opened document.

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