Example rules

The provided examples use the following fields in their rule expressions:

http.response.code (Response Status Code): Represents the HTTP status code returned to the client, either set by a Cloudflare product or returned by the origin server. Use this field to customize the response for error codes returned by the origin server or by a Cloudflare product such as a Worker.
cf.response.1xxx_code: Contains the specific error code for Cloudflare-generated errors. This field will only work for Cloudflare-generated errors such as 52X and 1XXX.

Custom JSON response for all 5XX errors

This example configures a custom JSON error response for all 5XX errors (500-599) in a zone. The HTTP status code of the custom error response will be set to 530.

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Custom error rule configuration:

Name: Custom JSON response for all 5XX errors
If incoming requests match > Custom filter expression:

Field Operator Value Logic
Response Status Code greater than or equal to 500 And
Response Status Code less than or equal to 599

If using the Expression Editor:
(http.response.code ge 500 and http.response.code le 599)
Response type: JSON response
Response code: 530
JSON response: {"message": "A server error occurred."}

Field	Operator	Value	Logic
Response Status Code	greater than or equal to	`500`	And
Response Status Code	less than or equal to	`599`

Required API token permissions

At least one of the following token permissions is required:

Response Compression Write
Config Settings Write
Dynamic URL Redirects Write
Cache Settings Write
Custom Errors Write
Origin Write
Managed headers Write
Zone Transform Rules Write
Mass URL Redirects Write
Magic Firewall Write
L4 DDoS Managed Ruleset Write
HTTP DDoS Managed Ruleset Write
Sanitize Write
Transform Rules Write
Select Configuration Write
Bot Management Write
Zone WAF Write
Account WAF Write
Account Rulesets Write
Logs Write
Logs Write

curl "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/rulesets/phases/http_custom_errors/entrypoint" \
  --request PUT \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --json '{
    "rules": [
        {
            "action": "serve_error",
            "action_parameters": {
                "content": "{\"message\": \"A server error occurred.\"}",
                "content_type": "application/json",
                "status_code": 530
            },
            "expression": "http.response.code ge 500 and http.response.code lt 600",
            "enabled": true
        }
    ]
  }'

This PUT request, corresponding to the Update a zone entry point ruleset operation, replaces any existing rules in the http_custom_errors phase entry point ruleset.

Custom HTML response with updated status code

This example configures a custom HTML error response for responses with a 500 HTTP status code, and redefines the response status code to 503.

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Custom error rule configuration:

Name: Custom HTML response for 500 errors
If incoming requests match > Custom filter expression:

Field Operator Value
Response Status Code equal to 500

If using the Expression Editor:
(http.response.code eq 500)
Response type: HTML response
Response code: 503

Field	Operator	Value
Response Status Code	equal to	`500`

HTML response:

<!DOCTYPE html><html><head><meta charset="utf-8"><title>Application unavailable</title></head><body><h1>Application temporarily unavailable</h1><p>Please try again later.</p></body></html>

Required API token permissions

At least one of the following token permissions is required:

Response Compression Write
Config Settings Write
Dynamic URL Redirects Write
Cache Settings Write
Custom Errors Write
Origin Write
Managed headers Write
Zone Transform Rules Write
Mass URL Redirects Write
Magic Firewall Write
L4 DDoS Managed Ruleset Write
HTTP DDoS Managed Ruleset Write
Sanitize Write
Transform Rules Write
Select Configuration Write
Bot Management Write
Zone WAF Write
Account WAF Write
Account Rulesets Write
Logs Write
Logs Write

curl "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/rulesets/phases/http_custom_errors/entrypoint" \
  --request PUT \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --json '{
    "rules": [
        {
            "action": "serve_error",
            "action_parameters": {
                "content": "<!DOCTYPE html><html><head><meta charset=\"utf-8\"><title>Application unavailable</title></head><body><h1>Application temporarily unavailable</h1><p>Please try again later.</p></body></html>",
                "content_type": "text/html",
                "status_code": 503
            },
            "expression": "http.response.code eq 500",
            "enabled": true
        }
    ]
  }'

This PUT request, corresponding to the Update a zone entry point ruleset operation, replaces any existing rules in the http_custom_errors phase entry point ruleset.

Custom HTML response for Cloudflare 1020 errors

This example configures a custom HTML error response for Cloudflare error 1020 (Access Denied).

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API

Custom error rule configuration:

Name: Custom HTML response for 1020 errors
If incoming requests match > Custom filter expression

Use the Expression Editor:
(cf.response.1xxx_code eq 1020)
Response type: HTML response

HTML response:

<!DOCTYPE html><html><head><meta charset="utf-8"><title>Access denied</title></head><body><h1>You do not have access to this page</h1><p>Contact us if you think this is an error.</p></body></html>

Required API token permissions

At least one of the following token permissions is required:

Response Compression Write
Config Settings Write
Dynamic URL Redirects Write
Cache Settings Write
Custom Errors Write
Origin Write
Managed headers Write
Zone Transform Rules Write
Mass URL Redirects Write
Magic Firewall Write
L4 DDoS Managed Ruleset Write
HTTP DDoS Managed Ruleset Write
Sanitize Write
Transform Rules Write
Select Configuration Write
Bot Management Write
Zone WAF Write
Account WAF Write
Account Rulesets Write
Logs Write
Logs Write

curl "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/rulesets/phases/http_custom_errors/entrypoint" \
  --request PUT \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --json '{
    "rules": [
        {
            "action": "serve_error",
            "action_parameters": {
                "content": "<!DOCTYPE html><html><head><meta charset=\"utf-8\"><title>Access denied</title></head><body><h1>You do not have access to this page</h1><p>Contact us if you think this is an error.</p></body></html>",
                "content_type": "text/html"
            },
            "expression": "cf.response.1xxx_code eq 1020",
            "enabled": true
        }
    ]
  }'

This PUT request, corresponding to the Update a zone entry point ruleset operation, replaces any existing rules in the http_custom_errors phase entry point ruleset.

Custom error asset created from a URL

This example configures a custom error rule returning a previously created custom error asset named 500_error_template for responses with a 500 HTTP status code.

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Custom error rule configuration:

Name: Serve asset for HTTP 500 errors
If incoming requests match > Custom filter expression:

Field Operator Value
Response Status Code equal to 500

If using the Expression Editor:
(http.response.code eq 500)
Response type: Custom error asset
Asset: 500_error_template

Field	Operator	Value
Response Status Code	equal to	`500`

Required API token permissions

At least one of the following token permissions is required:

Response Compression Write
Config Settings Write
Dynamic URL Redirects Write
Cache Settings Write
Custom Errors Write
Origin Write
Managed headers Write
Zone Transform Rules Write
Mass URL Redirects Write
Magic Firewall Write
L4 DDoS Managed Ruleset Write
HTTP DDoS Managed Ruleset Write
Sanitize Write
Transform Rules Write
Select Configuration Write
Bot Management Write
Zone WAF Write
Account WAF Write
Account Rulesets Write
Logs Write
Logs Write

curl "https://api.cloudflare.com/client/v4/zones/$ZONE_ID/rulesets/phases/http_custom_errors/entrypoint" \
  --request PUT \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --json '{
    "rules": [
        {
            "action": "serve_error",
            "action_parameters": {
                "asset_name": "500_error_template",
                "content_type": "text/html"
            },
            "expression": "http.response.code eq 500",
            "enabled": true
        }
    ]
  }'

This PUT request, corresponding to the Update a zone entry point ruleset operation, replaces any existing rules in the http_custom_errors phase entry point ruleset.

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