Supported Features

The following features are supported in the latest Cloudflare worker enforcer (Version 4.0.4):

Additional Activity Handler

The additional activity handler is a callback function passed to the enforcer. The enforcer runs this callback after sending page_requested or block activity to the collector, and before forwarding the request to the next step in the pipeline. A common use case of the additional activity handler is to set the score as a variable or header. Then the application can read the score and do what is defined within the application's logic.

Advanced Blocking Response (ABR)

In specific cases (e.g., XHR post requests), a full captcha page render might not be an option. In such cases the advanced blocking response returns a JSON object containing all the information needed to render a customized captcha challenge implementation - be it a popup modal, a section on the page, etc. This allows for flexibility and customizability in terms of how the captcha pages are displayed.

Block Page Captcha

A captcha page is one of the possible response types returned to the client as a result of a request blocked by the enforcer. In the case of a request with a high risk score, the user receives an HTML page presenting a captcha challenge to solve.

Block Page Hard Block

A block page is one of the possible response types returned to the client as a result of a request blocked by the enforcer. In the case of a request with a high risk score, the user receives an HTML block page that cannot be passed.

Block Page Rate Limit

Rate limit is one of the possible response types returned to the client as a result of a request blocked by the enforcer. Rate Limit means that in case of a request with high score, the user receives an HTML page with the rate limit response code (429).

Bypass Monitor Header

When enabling the enforcer for the first time, it is recommended to do so in monitor mode to collect data before actually starting to block user requests. Prior to switching the module mode to active_blocking entirely, it's also crucial to verify that the full blocking flow works as expected. This feature activates the full blocking flow even while in monitor mode if a particular header is present on the request.

Client IP Extraction

The real client IP is included in the information that the enforcer gathers and sends. When the request passes through a proxy or a load balancer before reaching the customer’s application, the module considers the internal IP as the user's IP by default. The px_ip_headers configuration defines which headers will contain the user's real IP, as set by a previous network component. The enforcer will try to extract the IP from these headers. If no IP exists, it will fall back to the IP of the machine it is directly connected to. If IP extraction is more complex than configuring a header, this enforcer also supports defining a custom function to extract the user IP.

CSP Support

Enabling csp_support protects from cross-site scripting attacks, code injections attacks and Magecart attacks that manipulate the website's functionality. During mitigation, Code Defender updates the policy to restrict the specific resources, and the browser blocks all communication with them.


Provides a way to include an additional custom .css file to add to the block page.

Custom Cookie Header

Allows to set a header name which is used to extract the PerimeterX cookies, instead of using the request cookies property.

Custom Logo

Adds a custom logo to the block page that will be shown to users. This aligns the block page with the customer's brand.

Custom Parameters

This feature enriches activities sent from the enforcer to PerimeterX with additional custom data. This data can include user information, session IDs, or other data that PerimeterX should have access to. These custom parameters are defined by a configurable function that must return an object that contains these custom parameters. There is a limit of 10 custom parameters.

Custom Request Handler

Allows for defining a custom JavaScript function that adds a custom response handler to the request.

Enforced Routes

Defines a list of routes (as strings or regular expressions) which should always be enforced with no exceptions.

Filter By Header

The ability to filter requests from the enforcer verification flow by specific header & its value.

Filter by IP

Filters out requests according to their IP address, avoiding unnecessary traffic in the enforcer verification flow and reducing operation costs.

Filter By Route

Routes (endpoints) specified here will not be blocked, regardless of the score they receive. A client request to an allowed route will not generate any risk or async activities.

Filter By User Agent

Filters out requests according to their user agent value, avoiding unnecessary traffic in the enforcer verification flow and reducing operation costs.

First Party

To prevent suspicious or unwanted behavior on the client side, some browsers or extensions (such as an Adblock extension) may deny the frontend JavaScript code from making requests to other domains. This prevents the PerimeterX sensor from making requests to the PerimeterX backends, which greatly limits PerimeterX's detection capabilities. To avoid this problem, first_party enables the enforcer to be used as a proxy for PerimeterX servers, and to serve content to the browser from a first party endpoint (i.e., an endpoint on the customer’s domain).

JS Ref

Provides a way to include a custom JS script to add to the block page. This script will run after the default JS scripts.

Login Credentials Extraction

Adds login information to risk API calls to identify compromised credentials as part of the Credentials Intelligence solution.

Mobile Support

The enforcer recognizes and handles requests coming from PerimeterX Mobile SDK. Because mobile apps do not add cookies as part of the HTTP requests, the PX cookies are sent as headers instead. Mobile user-agents may change during the flow of the app, so the mobile 'cookies' are not signed with user-agent and are considered as tokens.

Module Enable

This feature serves as an on/off switch for the entire module, providing a way to enable and disable all PerimeterX capabilities quickly and easily.

Module Mode

This feature controls the behavior of the enforcer by changing how it executes certain parts of the workflow. Most notably, different modes allow for analysis and fine-tuning of the enforcer behavior without serving block pages that affect end users.

Monitored Routes

Enables certain endpoints to be monitored rather than enforced by PerimeterX, even when the enforcer is in active blocking mode.

Sensitive Headers

The PerimeterX detector requires information about the HTTP request as part of its bot detections. Certain headers may contain information that should not be forwarded to other servers, including the PerimeterX backend. Configuring these header names as sensitive headers will remove these headers from requests sent to other backends by PerimeterX.

Sensitive Routes

Certain endpoints may require more stringent protection from bot attacks (e.g., endpoints that execute payments or handle personal information). In these cases, routes can be configured as sensitive routes, meaning risk API calls will be made even if the request contains a valid, unexpired cookie.

Snippet Injection

Auto inject a custom JS snippet to the client’s HTML pages which can be controlled remotely, allowing the flexibility to modify the snippet without having to deploy changes to the production environment. This feature helps ease the onboarding process as the snippet will be automatically added to the HTML response, simplify upgrades by not requiring to deploy changes to the production environment, and bypasses Ad blockers that attempt to block out going requests by the snippet to retrieve PerimeterX sensor.

Telemetry Command

The enforcer_telemetry activity is sent to PerimeterX servers whenever the enforcer receives a telemetry command. This activity provides information directly to PerimeterX about the current environment and configuration of the enforcer.

VID Extraction

The visitor ID (VID) is an identifier used by PerimeterX to identify clients during and across sessions. The VID is crucial for detection, and any mishandling of this feature could decrease its accuracy.

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