https://github.com/fingerprintjs/flow-cloudflare-worker

Cloudflare Worker for Flow.
https://github.com/fingerprintjs/flow-cloudflare-worker

audio-fingerprinting browser browser-fingerprint browser-fingerprinting detection device-intelligence fingerprint fingerprinting fingerprintjs fingerprintjs-pro fraud fraud-detection identification visitor-identifier

Last synced: 5 months ago
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Cloudflare Worker for Flow.

• Host: GitHub
• URL: https://github.com/fingerprintjs/flow-cloudflare-worker
• Owner: fingerprintjs
• License: mit
• Created: 2025-09-23T11:12:27.000Z (9 months ago)
• Default Branch: main
• Last Pushed: 2026-01-22T11:55:32.000Z (5 months ago)
• Last Synced: 2026-01-22T17:17:15.499Z (5 months ago)
• Topics: audio-fingerprinting, browser, browser-fingerprint, browser-fingerprinting, detection, device-intelligence, fingerprint, fingerprinting, fingerprintjs, fingerprintjs-pro, fraud, fraud-detection, identification, visitor-identifier
• Language: TypeScript
• Homepage:
• Size: 1.42 MB
• Stars: 2
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • Contributing: contributing.md
  • License: LICENSE
  • Codeowners: CODEOWNERS

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# Flow Cloudflare Worker

Cloudflare Worker for Fingerprint Flow.

> ⚠️ **Work in progress**: This is a beta version of the Flow Cloudflare Worker.

## Requirements

* [Fingerprint account](https://dashboard.fingerprint.com/signup) with the _Editor_ role assigned (or any role with _Edit configuration_ permission).

* A website served by Cloudflare. For maximum accuracy benefits, your website should be [proxied by Cloudflare](https://developers.cloudflare.com/dns/manage-dns-records/reference/proxied-dns-records/) (not DNS-only).

## Deploying

To use Fingerprint Flow, please deploy an instance of this worker [using the Fingerprint dashboard](https://dev.fingerprint.com/docs/rules-engine-and-flow-deployments-beta).

## Configuration

The worker is configured using a `wrangler.jsonc` file. An example file `wrangler.example.jsonc` is provided in the repository.

### Variables

-   `FP_REGION`: The Fingerprint region to use. Can be `us`, `eu`, or `ap`.

-   `WORKER_ROUTE_PREFIX`: A prefix for specific routes handled by the worker. This is used to avoid conflicts with other routes on the same domain.

-   `FP_PUBLIC_KEY`: Your Fingerprint public key.

-   `FP_SECRET_KEY`: Your Fingerprint secret key.

-   `FP_RULESET_ID`: Your Fingerprint ruleset ID.

    -   If not provided, the worker will default to a "monitor mode" where it still identifies the visitor for any request to `PROTECTED_APIS` but does not evaluate a ruleset for those requests.

-   `PROTECTED_APIS`: An array of APIs to protect with Fingerprint. Each object in the array should have a `method` and `url` property. The `url` pattern cannot be relative but it can contain wildcards.

    - Example: `[ { method: 'POST', url: 'https://example.com/sign-up/*' }]`

-   `IDENTIFICATION_PAGE_URLS`: An array of url patterns that cannot be relative but can contain wildcards where the Fingerprint identification script should be injected. 

    - Example: `[ 'https://example.com/login', 'https://example.com/signup/*' ]` 

## Architecture

### Worker

The Worker is a Cloudflare Worker that acts as a reverse proxy. Its main responsibilities are:

- Injecting the instrumentor and agent loader scripts on pages matching `IDENTIFICATION_PAGE_URLS`.

- Proxying Fingerprint API requests made by the JavaScript agent.

- When a request to `PROTECTED_APIS` are made, the worker reads signals injected by the instrumentor and sends a request to the Fingerprint Identification API. The API returns a specific action (e.g., allow/block) for the worker to take to with the protected API request.

The entry point for the worker is `src/worker/index.ts`.

### Instrumentor

The Instrumentor is a script that is injected into the page by the worker. It patches the `fetch` function to automatically add Fingerprint headers to protected API requests. The entry point for the instrumentor is `src/scripts/instrumentor/index.ts`.

The Instrumentor code is bundled and included in the Worker binary during the build process.

### Agent data processor

Located in `src/scripts/agent-data-processor/index.ts`, the Agent data processor is responsible for processing the data returned by the Fingerprint Identification API.

It is used for the HTML forms that are not sent via `fetch` or `XMLHttpRequest`. After the form is submitted, if it's `action` is listed in protected APIs, the agent processor script will be injected into the response to process agent data received from the initial identification request.