---
description: Reference information on the JSON object used in Lists API calls.
title: List JSON object
image: https://developers.cloudflare.com/og-docs.png
---

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# List JSON object

Last updated Aug 24, 2026|Copy as Markdown|[View as Markdown](https://mchen-ai-models-sync.previews.developers.cloudflare.com/waf/tools/lists/lists-api/json-object/index.md)|[Agent setup](https://mchen-ai-models-sync.previews.developers.cloudflare.com/agent-setup/)

## List object structure and properties

A JSON response for the [Lists API](https://mchen-ai-models-sync.previews.developers.cloudflare.com/api/resources/rules/subresources/lists/) has this structure:

```json
{
	"id": "2c0fc9fa937b11eaa1b71c4d701ab86e",
	"name": "my_list_name",
	"description": "List description.",
	"kind": "(ip|hostname|asn|redirect)",
	"num_items": 10,
	"num_referencing_filters": 2,
	"created_on": "2021-01-01T08:00:00Z",
	"modified_on": "2021-01-10T14:00:00Z"
}
```

This table summarizes the object properties:

| Property                        | Description                                                                                              | Constraints                                                                                                                                                  |
| ------------------------------- | -------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| idString                        | A UUIDv4 identifier generated by Cloudflare.                                                             | Unique, read only.Length: 32 characters.                                                                                                                     |
| nameString                      | An informative name for the list.                                                                        | Maximum length: 50 characters.Only alphanumeric and underscore (\_) characters are valid.A valid name satisfies this regular expression: ^\[a-zA-Z0-9\_\]+$. |
| descriptionString               | An informative summary of the list.                                                                      | Maximum length: 500 characters.                                                                                                                              |
| kindString                      | The type of data in the list.                                                                            | Valid values: ip, hostname, asn, redirect.                                                                                                                   |
| num\_itemsNumber                | The number of items in the list.                                                                         | Read only.                                                                                                                                                   |
| num\_referencing\_filtersNumber | The number of filters that reference this list.                                                          | Read only.                                                                                                                                                   |
| created\_onString               | The [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339) timestamp the list was created.            | Read only.                                                                                                                                                   |
| modified\_onString              | The [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339) timestamp when the list was last modified. | Read only.                                                                                                                                                   |

## List item object structure and properties

Each list type (IP address, hostname, ASN, redirects) can only contain items of the same type.

### IP address

A fully populated JSON object for an IP address list item has the following structure:

```json
{
	"id": "7c5dae5552338874e5053f2534d2767a",
	"ip": "10.0.0.1/32",
	"comment": "CF DNS server",
	"created_on": "2021-10-01T05:20:00.12345Z",
	"modified_on": "2021-10-01T05:20:00.12345Z"
}
```

### Hostname

A fully populated JSON object for a hostname list item has the following structure:

```json
{
	"id": "7c5dae5552338874e5053f2534d2767a",
	"hostname": {
		"url_hostname": "*.example.com"
	},
	"created_on": "2021-10-11T12:39:02Z",
	"modified_on": "2021-10-11T12:39:02Z"
}
```

### ASN

A fully populated JSON object for an ASN list item has the following structure:

```json
{
	"id": "7c5dae5552338874e5053f2534d2767a",
	"asn": 13335,
	"comment": "My provider's ASN",
	"created_on": "2021-10-11T12:39:02Z",
	"modified_on": "2021-10-11T12:39:02Z"
}
```

### URL redirect

A fully populated JSON object for a Bulk Redirect List item has the following structure:

```json
{
	"id": "7c5dae5552338874e5053f2534d2767a",
	"redirect": {
		"source_url": "https://example.com/blog",
		"target_url": "https://example.com/blog/latest",
		"status_code": 301,
		"include_subdomains": false,
		"subpath_matching": false,
		"preserve_query_string": false,
		"preserve_path_suffix": true
	},
	"created_on": "2021-10-11T12:39:02Z",
	"modified_on": "2021-10-11T12:39:02Z"
}
```

### Properties reference

The JSON object properties for a list item are defined as follows:

| Property           | Description                                                                                                                                                                                                                                                            | Constraints                                                                                                                                                                                                                         |
| ------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| idString           | A UUIDv4 identifier generated by Cloudflare.                                                                                                                                                                                                                           | Unique, read only.Length: 32 characters.                                                                                                                                                                                            |
| ipString           | An IP address or CIDR range.                                                                                                                                                                                                                                           | Applies only to custom lists with IP addresses (IP lists).Any of these formats can exist in the same custom list with IP addresses:IPv4 addressIPv6 addressIPv4 ranges as /8 through /32 CIDRsIPv6 ranges as /12 through /128 CIDRs |
| commentString      | An informative summary of the item.                                                                                                                                                                                                                                    | Maximum length: 500 characters.                                                                                                                                                                                                     |
| redirectObject     | An object that contains the definition of a URL redirect. Refer to [URL redirect parameters](https://mchen-ai-models-sync.previews.developers.cloudflare.com/rules/url-forwarding/bulk-redirects/reference/parameters/) for details.                                   | Applies only to Bulk Redirect Lists.                                                                                                                                                                                                |
| hostnameObject     | An object containing a url\_hostname property with a hostname value. Refer to [Lists with hostnames](https://mchen-ai-models-sync.previews.developers.cloudflare.com/waf/tools/lists/custom-lists/#lists-with-hostnames) for details on the supported hostname values. | Applies only to custom lists with hostnames.                                                                                                                                                                                        |
| asnInteger         | An ASN value.                                                                                                                                                                                                                                                          | Applies only to custom lists with ASNs.                                                                                                                                                                                             |
| created\_onString  | The [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339) timestamp when the list was created.                                                                                                                                                                     | Read only.                                                                                                                                                                                                                          |
| modified\_onString | The [RFC 3339](https://datatracker.ietf.org/doc/html/rfc3339) timestamp when the item was last modified.                                                                                                                                                               | Read only.                                                                                                                                                                                                                          |

For a detailed specification, refer to the [Lists API](https://mchen-ai-models-sync.previews.developers.cloudflare.com/api/resources/rules/subresources/lists/) documentation.

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