CivetWeb
Project mission is to provide easy to use, powerful, C/C++ embeddable web server with optional CGI, SSL and Lua support. CivetWeb has a MIT license so you can innovate without restrictions.
CivetWeb can be used by developers as a library, to add web server functionality to an existing application. It can also be used by end users as a stand-alone web server. It is available as single executable, no installation is required.