In South Korea, the HWP file format (*.hwp, *.hwpx) is mainly used by government agencies,
and it is also used by many companies who collaborate with government agencies.
It would be best if creator of the hwp file provided a dynamic link library that implemented the API,
Sadly, that doesn’t seem to be the case,
but at least, there is a reference document which defines the specification of *.hwp and *.hwpx documents.
https://www.hancom.com/etc/hwpDownload.do?gnb0=269&gnb1=271&gnb0=101&gnb1=140