> ## Documentation Index
> Fetch the complete documentation index at: https://www.twicecommerce.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Category tree

> A hierarchy that arranges your listings into paths, each group narrowing the listings by one condition, for browsing on your online store.

A category tree arranges your [listings](/docs/concepts/catalog/listings) into a hierarchy that shoppers browse on your online store. Collections stay flat. A tree stacks groups on top of each other, so a shopper can move from "Bikes" to "Electric" to "Under 20 kg" without leaving the shop.

Build trees under **Settings → Categories & Taxonomies**. Show them on the storefront with the **Category tree navigation** switch in the theme editor.

## How it works

A tree is made of **groups**. Each group narrows the listings by one condition, and a group shows the listings that match every condition along its path from the top.

| Group narrows by | Matches |
| - | - |
| **Collection** | Listings in one [collection](/docs/concepts/catalog/collections) |
| **Attribute value** | Listings carrying one value of an [attribute](/docs/concepts/admin/attributes) |
| **Category** | Listings in one [taxonomy category](/docs/concepts/admin/category-taxonomy) |
| **Tag** | Listings carrying one tag |
| **Nothing (a label)** | Nothing. The group is a heading for the groups beneath it |

A tree can go six levels deep. A group with no matching listings is left out of the storefront, so an empty branch never shows.

### How a path narrows

Take a store that resells designer clothing. The path **Women → Coats → Wool** holds three groups. **Women** is an attribute value, **Coats** is a category, and **Wool** is a tag.

The **Wool** group shows only the listings that are for women, in the coats category and tagged wool. Each step down removes listings, never adds them.

### Levels build groups for you

Adding every group by hand is slow for a large catalog. Add a **level** instead and TWICE creates the groups from a source:

| Level source | Creates one group for each |
| - | - |
| **Collections** | Collection you pick |
| **Attribute** | Value of the attribute you pick |
| **Categories** | Category in use, or every category beneath one you pick |
| **Tags** | Tag you pick |

Each level repeats under every group of the level above. An attribute level for audience followed by a categories level produces every audience and category path, such as Kids → Skis and Adults → Skis.

Hide the generated groups you do not want, and add your own groups next to them.

## Usage

### One collection can sit in several trees

A collection is a building block, not a place in the hierarchy. Use the same collection as a group in a tree for gift ideas and again in a tree organised by season. Changing the collection changes every group that uses it.

### A listing can appear in several places

Because groups match by condition, a listing appears under every path it matches. A venue hire listing tagged "weddings" and "outdoor" shows up under both groups.

When a listing sits in more than one tree, the first tree in your list wins ties. The order of your trees sets the breadcrumb on the listing page and the canonical URL of its shop pages. Drag a tree to reorder the list.

### Trees are off until you switch them on

A new store shows collections only. Switch on **Category tree navigation** in the theme editor to replace the flat shop with your trees. Switch it off and the store goes back to collections, with every tree kept.

### Deleting a tree is safe for your catalog

Deleting a tree removes the tree and its groups. Your listings, collections, attributes and tags are not affected.

> [!NOTE]
>
> A category tree is not the [Category Taxonomy](/docs/concepts/admin/category-taxonomy). The taxonomy is a fixed classification that says what a listing is, shared by every account. A tree is your own arrangement of listings for shoppers, and it can use taxonomy categories as one kind of condition.

## Visibility and permissions

Category trees follow the collection permissions. **Create and edit collections** lets a user build and edit trees, **Delete collections** lets them delete trees, and **View collections** shows the trees read-only. For the full role matrix, see [Users & Roles](/docs/settings/users-roles).

## Related articles

> **[Build a category tree](/docs/guides/catalog/build-a-category-tree)**
>
> Build a tree and show it in your storefront navigation.

> **[Categories & Taxonomies](/docs/settings/categories-taxonomies)**
>
> The settings view where you list, order and edit trees.

> **[Collections](/docs/concepts/catalog/collections)**
>
> The flat groups a tree can use as building blocks.

> **[Category Taxonomy](/docs/concepts/admin/category-taxonomy)**
>
> The fixed classification of what a listing is.


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