Enforcement of rules for the shipping of items

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a user interface for enforcement of shipping rules. In one aspect, a method includes accessing regulation information/data, the regulation information/data being a multi-level hierarchy of nodes arranged in a tree structure, each node specifying one or more keywords, wherein the nodes comprise one or more starting nodes having one or more child nodes and having no parent nodes, one or more intermediate nodes having at least one of a child node and a parent node, and one or more end nodes having at least one parent node and no child nodes. Determining, that a particular keyword from the received one or more keywords matches a keyword of a node in the hierarchy. Determining, a level and a type of the node in the hierarchy, wherein the type of the node specifies whether the node is one of a starting node, an intermediate node, and an end node. The method then identifies, based, at leastin part, on the level and