An simple PasteBin uses pygments to generate html and Flask as background.
sudo docker run --restart=always --name pastebin -p 80:80 weicheng97/pastebin:2.0
Do not try to just use app.run. Flask has serious problem on performance.
gunicorn -w 4 -b 0.0.0.0:80 PasteBinWeb:app
Just open it and enjoy pasting.
visit http://yourdomain/all to find all files ordered by newest pasted time.
Post to root URL and server receive two parameters [syntax,content], quite easy.