I would like to use the Bing Hybrid map in a Web Application. I have so far configured everything with little change to the code other than UI stuff. Is this possible?
If you have a valid bing maps key then I would suggest you go through this blog post by esri in order to learn how to add bing maps to your ARcGIS online account. Once you have added them there, they should automatically appear on your Web App builder basemaps widget after you close and reopen your app.