I've recently started an android app (using Unity) and users will need to upload a (~200kb) file somewhere, and have another user download it later. I was planning to use Dropbox as they have a 20gb daily bandwith allowance, but I can't find a way to upload files to my dropbox account through code. Is there a way to upload to a dropbox account using C#?
I know it's possible using PHP, and I could have the user upload to a web server and then send it to a public dropbox folder. Though all the web servers I have found do not allow file storage/sending like that.
So also, what web servers do popular apps use to store all their data and have enough bandwith? If my app did become popular, I can't find a web server to handle thousands or more of concurrent users downloading and uploading.
Have a look at Dropbox Rest API and Unity's WWW-Class.
You should be able to consume the Dropboxapi via Unity.