I used Cratejoy to handle the e-commerce backend, so the extent of it was some minor HTML/CSS work. There's existing solutions for Shopify that do the same as well, so no programming needed.
Later on (still running 5 years later), when I got back into coding again, I got rid of Cratejoy and wrote the backend from scratch in Ruby.
Later on (still running 5 years later), when I got back into coding again, I got rid of Cratejoy and wrote the backend from scratch in Ruby.