Here's the discussion of the initial release:

https://news.ycombinator.com/item?id=19214387

The inability to handle embedded NULs (issue #40) felt like cheating, but that has been fixed.

It looks like I can fetch a number as a string, so I can read into a decimal type. I'll have to try that. Edit: nope, doesn't work. "The JSON element does not have the requested type."