Returns the curated niche taxonomy (up to four levels, e.g. "Health > Exercise > Gym") with, for each category, its id, path, level, parent and how many active profiles are categorized under it including its sub-niches. Only categories with at least minProfiles profiles in their subtree are returned (default 5), so every id you get back yields a real result set. Pass a categoryId to search_outliers, search_profiles or niche_trends to scope them to the creators in that niche; the filter always covers the subtree. Free to call and cached, so call it at the start of a session and reuse the ids. Categories are assigned per creator by our categorizer (reviewed by hand for new niches), which makes this filter more precise than a keyword over captions: it catches creators whose captions are hashtag-only or not in English.

Cost: free.