Cutelyst
Web Framework built on top of Qt, using the approach of Catalyst
...With Qt, you already can write applications for Windows, Linux, Android, MacOS, and iOS using the same source code, Cutelyst allows you to share your C++ code with your web application. Cutelyst has a WSGI server that supports HTTP/1.1, HTTP/2, FastCGI, and WebSockets, it can even be embedded in your application if you like. It also features a plugin for uWSGI which gives us support for HTTP/1.0, FastCGI, and uWSGI protocols but is slower and doesn't support WebSockets. Running standalone or behind a web server is really easy. With your application logic written in C++ your application get's really small, a full CMS (like this one) uses around 5MB of RAM which can be shared with other instances of the same application.