The server is written in Go. The news scraper is written in python. I don't have the full list of sites offhand, but I'll try and get back to this comment!
You wrote elsewhere that your output HTML is highly optimized. I viewed the source of the page and I can see that it contains the CSS inside <style> tags and images embedded as base64 encoded text - what software do you use to generate this output?
The python scraper base64 encodes all the images, so that data is prepared for the web server. The python library being used is PIL. The CSS is hand-written in a Go template. The goal was to have all the rendering done in a single request, so I choose to embed the CSS and relax the CSP on styles.
