NPT is not API. The most common API is generally called "8 round" and is similar to NPS. API also has buttress , 10 round, and a few reverse engineered proprietary threads like PH 6. I will mention there may be a hundred different proprietary threads used on API casing and tubing.
Thanks team I have actually already searched in google but google sometimes doesn't give you a straightforward answer that's why i wrote in here.....how about LP (Line pipe) thread please ? also not API thread ?