Hi, I write solutions like this one all the time. Please, refer to my portfolio and you will find that most of my projects (95%) are Office integrations that communicates with Web-Services in the cloud.
Regarding the specifics of your project, your solution will contain two components, one would be the server side which will contain a web-service exposing all the endpoints needed so external applications can communicate to; and the client side, which is an Excel integration which will communicate with the Web-Service to Send/Receive all information needed depending on the values/data stored on the Spreadsheet.
In my case it will surely be ery easy, so I placed 10 days on my bid, 8 to deliver your solution and 2 more just in case you need anything else.
Well, I think that is all by now. If you have a question just send a message.
Regards,
Joe.