Create a new project
Disable all APIs
Enable Google Apps Marketplace API
Create a web application Client ID
- Name (max 15 chars)
- Description (max 200 chars)
- Individual install (bool)
- Icons (see assets)
- Support URLs (see assets)
- Oauth scopes
- Universal Navigation extension
- URL
- GMail Contextual gadget extension
- Extractor URL: google.com:MessageIDExtractor
- Gadget URL: https://gpcsolutions.fr/gadgets/hello_world_gadget.xml
- Scopes
- Mail - Message Ids
PNG format
- 128x128
- 96x96
- 48x48
- 32x32
HTML format
Published URL
Add &nogadgetcache=1
to GMail URL to make sure the latest version is loaded, not a Google cached version.