A few months ago, I spent a couple days reverse engineering the Snapchat protocol and wrote a quick and dirty library to use it in your own PHP apps: https://github.com/tlack/snaphax Today Snapchat has written me requesting that I take it offline: Hi Thomas, I'm writing to ask that you remove Snaphax from github and no longer publish or distribute it. Snapchat does not permit third party software to access our API and we consider Snaphax to be an unlawful circumvention device under 17 U.S.C. § 1201(a)(1). Please confirm that it has been removed by end of day Monday, July 22nd. Thank you, Micah Schaffer Snapchat, Inc. I haven't had much time to really finish Snaphax (and I doubt I ever will) but I strongly support the idea that third party software should be able to interact with the services I use every day. I am under the impression that reverse engineering is still protected under fair use doctrines. Is this the case? How should I respond, if at all?