I think Simple might have one, though I only came across this repo referencing Simple: https://github.com/wearefractal/bank
check devtools when logged into simple.
I want to completely disclose Neocities financing, and lack of API for safely doing this has been a frustrating problem.
Put varnish in front of your API to act as a caching layer and prevent anyone from causing your server to overload the bank API.