Inky is kinda like a preprocessor for HTML created by Zurb, specifically designed for responsive emails.
I'm sure a lot of us have hand-coded HTML emails (I do it regularly) and know that it's typically
<table></table> soup. It's not even just the tables that are annoying, but the fact that there are so many of them nested to do even fairly simple things it's hard to keep straight.
Inky's appeal is pretty clear from the first demo in their docs: