I maintain a website called calmcode.io. It's a website that is shared by a lot of folks on social media which means that I'd like proper images to automatically generate when folks share it. Most blogging frameworks generate these for you, but since calmcode is rendered by custom python code I needed to implement this myself.
And here's where the tricky stuff starts. Twitter does it differently than linkedin, which in turn does it differently than slack. Figuring this stuff out manually was a huge pain. And then I learned about metatags.io.
It's great! You basically have a GUI which shows you what all the different social platforms will render like. Once you like what you see, it can even generate the meta tags for you!
Figured I should mention it somewhere. This is a huge timesaver.