Custom Gmail Extension Widget Not Appearing in Interface

Other Questions Gmail
1

I’m working on creating a custom Gmail extension widget but it’s not showing up in my Gmail interface. I’ve created the widget.xml file following all the documentation guidelines. The docs mention creating a manifest file, but from what I understand, this isn’t needed anymore since we can use the Google Apps Marketplace SDK instead.

I’ve set up everything through the console.developers.google.com and enabled all the necessary settings, but my widget still doesn’t appear in Gmail. This has been frustrating me for weeks now.

Here’s my widget.xml configuration:

<?xml version="1.0" encoding="UTF-8"?>
<Module>
<ModulePrefs author="Tech Solutions" height="400" author_email="[email protected]" author_location="USA">
<Require feature="dynamic-height"/>
<Require feature="views" />
<Require feature="google.contentmatch">
<Param name="extractors">google.com:MessageIDExtractor</Param>
<Param name="extractors">google.com:SenderEmailExtractor</Param>
</Require>
</ModulePrefs>
<Content type="html" view="card">
<![CDATA[
<div>Custom Email Integration Tool</div>
<script>console.log('Widget loaded successfully')</script>
]]
></Content>
</Module>

Can anyone experienced with Gmail widget development help me figure out what might be wrong?

2

yeah, dancingbutterfly’s right - the API is deprecated. but also check your gmail version. some companies still use the old interface where add-ons break. had this exact prob at work last month. switch to the new gmail UI first before you rebuild everything.

3

I had the same problem! Turns out it wasn’t the XML code - it was deployment. Your widget.xml looks fine, but you need to deploy it to a publicly accessible URL. Gmail won’t load widgets stored locally or on private servers. I had to host mine on Google App Engine before it showed up in Gmail. Also, double-check your OAuth scopes in the developer console, especially Gmail API permissions. And make sure your test Gmail account is in the authorized test users list - the widget won’t appear without that setup.

4

That widget.xml structure you posted uses the old Google Gadgets API format. Gmail killed support for those contextual gadgets in 2019. You’ll need to rebuild this as a Gmail Add-on using Google Workspace Add-ons - it’s completely different now with Apps Script and JSON manifest files instead of XML. The old widget.xml method is dead, no matter how you configure it. I learned this the hard way migrating an old project last year.