I am in the need to find a really lightweight headless browser to use in a Selenium project. PhantomJS would have been the perfect choice if it wasn't discontinued. Right now I'm using Firefox in headless mode but it's not suitable to my needs. My application spawns a lot of concurrent threads and each of them needs to open a new browser process, needless to say that Firefox (or worst, Chrome) eats all of my RAM with just 20 processes. I was thinking of using CefSharp.OffScreen but unfortunately I need a portable browser and CefSharp isn't one of them. Any suggestions?