This tool utilizes the WMF Labs databases to generate very fast category trees and tree intersections.

Language (required)
Project (required)
Root categories
(One category per line) (required)
Namespace (0=articles, 6=files)
Depth (-1=unlimited)
Max results
Offset
Format
Image usage
Sparse
Group
Count
JSONP Name of callback function (JSON only)
(add &norun to the URL to get this pre-filled form again)