There are vast array of shrimp pastes use in southern China and throughout S.E. Asia. There are differences from country to country, and a great many regional variations. In general, kapi, the the main form in Thailand, can be substituted for belachan (also spelled belacan, blachang), the main form in Malaysia, and terasi (also spelled trassi), the most common Indonesian variety. With some culinary improvisation, kapi can be tweaked with sugar, water, fish, fish sauce etc., to mimic regional varieties only available locally. To toast kapi (which enhances its flavour) without having to move out of your home for a week, wrapping a piece in tinfoil and sautéing it in a dry skillet will mitigate the "aroma".