Oh yup, had no idea that existed! Looks pretty similar, just slightly different syntax using <sui-header ...> instead of <Header ...> for example.
The backends themselves will definitely be in python. I also want the API itself to be portable/modular enough that others will be able to use it for other project needs as well. SDBS I feel was trying to go that route, but it wasn't customizable enough for my needs in building a DB.