> For the complete documentation index, see [llms.txt](https://docs.overflowcms.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.overflowcms.com/editor-guide/collections-and-fields.md).

# Collections & Fields

## Collections & Fields

A collection is a content type you define yourself — not a fixed template. Give it a name (the slug is derived automatically, e.g. "Blog" → `blog`) and a list of fields.

![The Fields tab of a collection, showing the field-schema editor](https://overflowcms.com/images/docs-screenshots/collection-fields.png)

### Field types

| Type        | Stores                                 | Indexable     | Notes                                                                                                      |
| ----------- | -------------------------------------- | ------------- | ---------------------------------------------------------------------------------------------------------- |
| `text`      | Plain string                           | Yes (text)    | Optional max length                                                                                        |
| `richText`  | HTML string                            | No            | Authored with a rich-text editor (bold/italic/H2/bullet list/quote); bind with `data-oc-html` in the embed |
| `image`     | MediaRef object                        | No            | See Images & Media                                                                                         |
| `number`    | Integer or decimal                     | Yes (numeric) | Optional min/max                                                                                           |
| `date`      | ISO-8601 datetime string               | Yes (numeric) |                                                                                                            |
| `boolean`   | true/false                             | Yes (numeric) |                                                                                                            |
| `option`    | One value from a fixed list you define | Yes (text)    | Enforced against your option list on save                                                                  |
| `reference` | Another item's id                      | Yes (text)    | **Requires Pro+.** Resolved one level deep at read time                                                    |
| `video`     | MediaRef object                        | No            | **Requires Pro+.** See Images & Media                                                                      |

Every field has a **key** (camelCase, e.g. `publishedDate`) — this is both the JSON property name in the item's data and the value you put in `data-oc-field` in Webflow. Renaming a field's **label** never changes its key, specifically so existing item data doesn't get orphaned; you only change the key if you edit it explicitly, and the dashboard warns you when a collection already has items.

### Indexed fields

Mark a field **indexed** to make it usable in the public API's `sort`/`filter` query params (and in the embed's `data-oc-sort`). Indexed values are extracted into a separate lookup table when an item is saved, which is what lets sorting and filtering compile to real indexed SQL instead of scanning JSON blobs — it's also why not every type is indexable (rich text and images aren't meaningful to sort by).

### Editing a collection later

Collections aren't locked in after creation. From the collection's **Fields** tab you can rename it, add/remove/reorder fields, and change a field's type or config — changes apply to new and existing items. Deleting a collection deletes all of its items; there's a confirmation step because it can't be undone.


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