Create a request header transform rule via API

Use the Rulesets API to create Request Header Transform Rules via API. Refer to the Rules examples gallery for common use cases.

Basic rule settings

When creating a request header transform rule via API, make sure you:

Set the rule action to rewrite.
Define the header modification parameters in the action_parameters field according to the operation to perform (set or remove header).
Deploy the rule to the http_request_late_transform phase at the zone level.

Procedure

Follow this workflow to create a request header transform rule for a given zone via API:

Use the List zone rulesets operation to check if there is already a ruleset for the http_request_late_transform phase at the zone level.
If the phase ruleset does not exist, create it using the Create a zone ruleset operation. In the new ruleset properties, set the following values:
- kind: zone
- phase: http_request_late_transform
Use the Update a zone ruleset operation to add a request header transform rule to the list of ruleset rules. Alternatively, include the rule in the Create a zone ruleset request mentioned in the previous step.

Make sure your API token has the required permissions to perform the API operations.

Example requests

Example: Add an HTTP request header with a static value

The following example sets the rules of an existing phase ruleset ($RULESET_ID) to a single request header transform rule — adding an HTTP request header with a static value — using the Update a zone ruleset operation. The response will contain the complete definition of the ruleset you updated.

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/$ZONE_ID/rulesets/$RULESET_ID \
  --request PUT \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --json '{
    "rules": [
        {
            "expression": "(starts_with(http.request.uri.path, \"/en/\"))",
            "description": "My first request header transform rule",
            "action": "rewrite",
            "action_parameters": {
                "headers": {
                    "X-Source": {
                        "operation": "set",
                        "value": "Cloudflare"
                    }
                }
            }
        }
    ]
  }'

{
  "result": {
    "id": "<RULESET_ID>",
    "name": "Zone-level Late Transform Ruleset",
    "description": "Zone-level ruleset that will execute Late Transform Rules.",
    "kind": "zone",
    "version": "2",
    "rules": [
      {
        "id": "<RULE_ID>",
        "version": "1",
        "action": "rewrite",
        "action_parameters": {
          "headers": {
            "X-Source": {
              "operation": "set",
              "value": "Cloudflare"
            }
          }
        },
        "expression": "(starts_with(http.request.uri.path, \"/en/\"))",
        "description": "My first request header transform rule",
        "last_updated": "2021-04-14T14:42:04.219025Z",
        "ref": "<RULE_REF>"
      }
    ],
    "last_updated": "2021-04-14T14:42:04.219025Z",
    "phase": "http_request_late_transform"
  },
  "success": true,
  "errors": [],
  "messages": []
}

Example: Add an HTTP request header with a dynamic value

The following example sets the rules of an existing phase ruleset ($RULESET_ID) to a single request header transform rule — adding an HTTP request header with a dynamic value — using the Update a zone ruleset operation. The response will contain the complete definition of the ruleset you updated.

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/$ZONE_ID/rulesets/$RULESET_ID \
  --request PUT \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --json '{
    "rules": [
        {
            "expression": "(starts_with(http.request.uri.path, \"/en/\"))",
            "description": "My first request header transform rule",
            "action": "rewrite",
            "action_parameters": {
                "headers": {
                    "X-Bot-Score": {
                        "operation": "set",
                        "expression": "to_string(cf.bot_management.score)"
                    }
                }
            }
        }
    ]
  }'

{
  "result": {
    "id": "<RULESET_ID>",
    "name": "Zone-level Late Transform Ruleset",
    "description": "Zone-level ruleset that will execute Late Transform Rules.",
    "kind": "zone",
    "version": "2",
    "rules": [
      {
        "id": "<RULE_ID>",
        "version": "1",
        "action": "rewrite",
        "action_parameters": {
          "headers": {
            "X-Bot-Score": {
              "operation": "set",
              "expression": "to_string(cf.bot_management.score)"
            }
          }
        },
        "expression": "(starts_with(http.request.uri.path, \"/en/\"))",
        "description": "My first request header transform rule",
        "last_updated": "2021-04-14T14:42:04.219025Z",
        "ref": "<RULE_REF>"
      }
    ],
    "last_updated": "2021-04-14T14:42:04.219025Z",
    "phase": "http_request_late_transform"
  },
  "success": true,
  "errors": [],
  "messages": []
}

Example: Remove an HTTP request header

The following example sets the rules of an existing phase ruleset ($RULESET_ID) to a single request header transform rule — removing an HTTP request header — using the Update a zone ruleset. The response will contain the complete definition of the ruleset you updated.

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/$ZONE_ID/rulesets/$RULESET_ID \
  --request PUT \
  --header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
  --json '{
    "rules": [
        {
            "expression": "(starts_with(http.request.uri.path, \"/en/\"))",
            "description": "My first request header transform rule",
            "action": "rewrite",
            "action_parameters": {
                "headers": {
                    "cf-connecting-ip": {
                        "operation": "remove"
                    }
                }
            }
        }
    ]
  }'

{
  "result": {
    "id": "<RULESET_ID>",
    "name": "Zone-level Late Transform Ruleset",
    "description": "Zone-level ruleset that will execute Late Transform Rules.",
    "kind": "zone",
    "version": "2",
    "rules": [
      {
        "id": "<RULE_ID>",
        "version": "1",
        "action": "rewrite",
        "action_parameters": {
          "headers": {
            "cf-connecting-ip": {
              "operation": "remove"
            }
          }
        },
        "expression": "(starts_with(http.request.uri.path, \"/en/\"))",
        "description": "My first request header transform rule",
        "last_updated": "2021-04-14T14:42:04.219025Z",
        "ref": "<RULE_REF>"
      }
    ],
    "last_updated": "2021-04-14T14:42:04.219025Z",
    "phase": "http_request_late_transform"
  },
  "success": true,
  "errors": [],
  "messages": []
}

Required API token permissions

The API token used in API requests to manage Request Header Transform Rules must have at least the following permissions:

Transform Rules > Edit
Account Rulesets > Read

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