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

# Collection Fields Reference

> The collection.* catalog — why the Collection binding prefix is still tub, which Collection values resolve, and the two metadata paths the editor offers that never populate

The Collection namespace reads the Collection that the scanned Item belongs to — its name, its
description, its cover image. Every Item in the Collection sees the same values, which is what
makes these bindings useful for branding a URL or a Page and largely useless for identifying a
specific Item.

## Available fields

| Binding                  | Type   | Notes                                                                                          |
| ------------------------ | ------ | ---------------------------------------------------------------------------------------------- |
| `collection.name`        | string | The Collection's display name, for example `Heavy Equipment`                                   |
| `collection.description` | string | Free-text description; often empty                                                             |
| `collection.image_url`   | string | URL of the Collection's cover image                                                            |
| `collection.items_name`  | string | The custom label for this Collection's Items, for example `Machines`. Empty unless you set one |
| `collection.id`          | string | QRtub's internal identifier for the Collection — long and opaque                               |
| `collection.created_at`  | date   | When the Collection was created, as an ISO timestamp                                           |
| `collection.updated_at`  | date   | When the Collection was last changed, as an ISO timestamp                                      |

There are no custom fields at Collection level. Custom fields are defined *by* a Collection and
belong to its Items, so they are read as `item.*` — see
[Item Fields Reference](/destinations/item-fields).

## `collection.metadata` is not a binding surface

`collection.metadata` exists, but it holds QRtub's own configuration for the Collection — its field
definitions, its Link generation rule, its scan-behavior defaults. Nothing in it is a stable,
documented value to bind against, and its internal structure can change between releases.

Two paths under it deserve a specific warning, because the editor's property picker offers them
as if they were real data:

* `collection.metadata.page.is_public`
* `collection.metadata.organizationName`

**Neither is ever populated.** No part of QRtub stores a value at either path, so both resolve to
nothing. In a condition that means the whole expression evaluates to `false` and the rule never
fires; in a Destination URL it means every binding in that URL counts as unresolved and the
Destination is skipped. If you need to know whether a Page is private, check the Collection's
privacy setting in the interface rather than trying to read it from a binding.

## When Collection fields are worth using

The honest answer is: less often than Item fields. A `collection.*` value is identical for every Item in
the Collection, so it cannot identify anything. The cases where it does earn its place are:

* **Passing your own grouping to another system**, so a work-order URL arrives tagged with the
  Collection it came from: `https://cmms.example.com/wo/new?asset={{item.item_number}}&group={{collection.name}}`.
* **Labeling a shared Page template** with `{{collection.name}}` so one template reads correctly across
  several Collections.

Both are cosmetic. If the receiving system needs to distinguish one Item from another, bind an
`item.*` field. And remember that values are inserted with no URL encoding, so a Collection name
containing a space or an ampersand will break the URL it is inserted into — see
[Field Bindings & URL Templates](/destinations/field-bindings).

## Related

* [Field Bindings & URL Templates](/destinations/field-bindings) — the `{{ }}` syntax, encoding and missing-value rules
* [Item Fields Reference](/destinations/item-fields) — the `item.*` catalog, including custom fields
* [What Is a Collection?](/collections/overview) — the entity these fields describe
* [Page Privacy: Public vs. Private](/pages/page-privacy) — where the public/private setting actually lives