Under-ConScript Unicode Registry
USCUR is the "Unicode Conscript Registry". It attempts to standardize the unicode codepoints in the Private Use Area for constructed scripts that wouldn't be accepted in Unicode.
sitelen pona
sitelen pona has a USCUR specification
There are instructions for making sitelen pona UCSUR work on your computer
Web-based text converters exist
Defined codepoints (2022-05-20)
Note that these will render as "missing glyph" boxes unless you have a UCSUR-compatible font installed
pu:
ku suli:
ku lili:
special characters: