the short answer to your question is no. The Flex app can of course be displayed inside a simple HTML page, just like the template auto-generated by Flex. However, this approach does not allow you receive an uploaded file, validate it, store it in the server file system etc. For that you will have to write some kind of server-side code. The language you use will depend on what you are comfortable with, and what technology is available on the server in question, but you will need to write something.