Can I generally use off-the-shelf postgresql bindings in most languages with CitusDB, or are there things about CitusDB that would require custom bindings? If the latter is true, for what languages are bindings available (ruby/node.js/crystal...)?
The off the shelf Postgres drivers work. We're a pure Postgres extension so you don't need anything exotic there just a standard Postgres driver. When it comes to the application side of things it depends a little bit more there on how you may structure your queries. To help out there we have a few libraries (for Rails[1] and Django[2]) and more coming.
[1] https://www.citusdata.com/blog/2017/11/14/scale-out-your-dja...