---
title: Custom errors parameters · Cloudflare Rules docs
description: Custom error rules define when a custom error gets triggered and the content that is served to visitors. Rule parameters are the following:
source_url:
  html: https://bd468052.preview.developers.cloudflare.com/rules/custom-errors/reference/parameters/index.md
  md: https://bd468052.preview.developers.cloudflare.com/rules/custom-errors/reference/parameters/
---

## Custom error rules

Custom error rules define when a custom error gets triggered and the content that is served to visitors. Rule parameters are the following:

### Response type

API name: *N/A* (handled via [`asset_name`](#asset) and [`content_type`](#response) parameters)

The content type of the inline response to send to the website visitor (JSON, HTML, Text, or XML), or **Custom error asset** if sending the content of a custom error asset.

When using the API you must either set the `asset_name` or set both the `content_type` and `content` parameters. Refer to [JSON response / HTML response / Text response / XML response](#response).

### Response code

API name: **`status_code`** Integer Optional

The HTTP status code of the response. If provided, this value will override the current response status code.

The status code must be between `400` and `999`.

### Asset

API name: **`asset_name`** String Optional

The name of the [custom error asset](#custom-error-assets) you previously uploaded (in the dashboard, you can create an asset when creating the rule). The asset may include [error tokens](https://developers.cloudflare.com/rules/custom-errors/reference/error-tokens/) that will be replaced with real values before sending the error response to the visitor.

A custom error rule can only reference an asset defined in the same scope as the rule (that is, in the same zone or account).

In the dashboard, this parameter is only available when you select `Custom error asset` in **Response type**.

When using the API, you must provide either the `asset_name` or the `content` parameter.

### JSON response / HTML response / Text response / XML response

API names: **`content`** String Optional and **`content_type`** String Required

The response body to return. It can include [error tokens](https://developers.cloudflare.com/rules/custom-errors/reference/error-tokens/) that will be replaced with real values before sending the error response to the visitor.

You must provide either the `asset_name` or the `content` parameter.

The maximum content size is 10 KB.

When using the API you must also set the `content_type` parameter, which defines the content type of the returned response. The value must be one of the following:

* `text/html`
* `text/plain`
* `application/json`
* `text/xml`

Warning

If you create an HTML error response, make sure the `referrer` meta tag is not present in the HTML code since it will disrupt [Cloudflare challenges](https://developers.cloudflare.com/fundamentals/security/cloudflare-challenges/):

```html
<meta name="referrer" (...) />
```

## Custom error assets

A custom error asset corresponds to a web resource such as an HTML web page (including any referenced images, CSS, and JavaScript code) that Cloudflare fetches and saves based on a URL you provide, to be served to visitors as an error page.

Custom error assets have the following parameters:

### Asset name

API name: **`name`** String Required

The name of the custom error asset. Example value: `"500_error_template"`.

An asset name can contain the following characters:

* Uppercase and lowercase letters (`A-Z` and `a-z`)
* Numbers (`0-9`)
* The underscore (`_`) character

The maximum length is 200 characters.

### Description

API name: **`description`** String Optional

A string describing the custom error asset. Example value: `"Standard 5xx error template page"`.

### Asset address

API name: **`url`** String Required

The URL of the page you want Cloudflare to fetch and store, to be served later to visitors as error pages according to the configured [custom error rules](#custom-error-rules). Example value: `"https://example.com/errors/500.html"`.

When you create or update an asset and provide a URL, Cloudflare collects any images, CSS, and JavaScript code used in the page, minifies the content, and saves it internally.

The content of the page at the specified URL may include [error tokens](https://developers.cloudflare.com/rules/custom-errors/reference/error-tokens/) that will be replaced with real values before sending the error response to the visitor.

When using the dashboard, you can later trigger another fetch to get the latest version of the page along with its resources, and store it internally.

When using the API, if you update an asset and provide the same URL, Cloudflare will fetch the URL again, along with its resources, and store it internally.

The maximum asset size is 1.5 MB.
