Photon vs Ultralight: What are the differences?
Developers describe Photon as "Framework for Electron apps". The fastest way to build beautiful Electron apps using simple HTML and CSS. Underneath it all is Electron. Originally built for GitHub's Atom text editor, Electron is the easiest way to build cross-platform desktop applications. On the other hand, Ultralight is detailed as "A lightweight, pure-GPU, HTML UI renderer for native apps". intended to be used for rendering HTML UI within games and desktop apps. The API is currently available for C++ and supports OpenGL 3.2+, Direct3D 11, and Metal 2.
Photon and Ultralight can be primarily classified as "Cross-Platform Desktop Development" tools.
Photon and Ultralight are both open source tools. It seems that Photon with 9.04K GitHub stars and 518 forks on GitHub has more adoption than Ultralight with 996 GitHub stars and 52 GitHub forks.