The Thai name for fermented shrimp paste is kapi.
Kapi is a dark, pungent Thai condiment made primarily from finely crushed shrimp or krill mixed with salt and fermented. The mixture develops a dense texture and powerful savory aroma as it matures. In Thai cooking, kapi is used in curry pastes, dipping sauces, and spicy nam phrik preparations.
One of the best-known uses is nam phrik kapi, a chili-based dip often served with fried pla thu, or short mackerel, alongside raw, steamed, or fried vegetables. Kapi is also an important flavor base in many Thai curry pastes, including pastes used for dishes such as kaeng som.
Kapi is not the same as nam pla, which is a liquid fermented fish sauce. It is also different from prik kee noo, the Thai name for small bird’s-eye chilies, and pla ra, a fermented fish paste. Another possible mix-up is mun kung, an orange, oily shrimp-head product that is closer to shrimp tomalley than to solid fermented shrimp paste.