Recaptcha Transaction Defense Integrator

reCAPTCHA Transaction Defense Integrator

This skill helps you integrate reCAPTCHA Transaction Defense into your Node.js application and automate the "ground truth" feedback loop by listening to chargeback notifications from Payment Service Providers (PSPs) like Stripe and Adyen.

Prerequisites

1. Google Cloud Project: reCAPTCHA Enterprise must be enabled. The Fraud Prevention feature must also be enabled in the reCAPTCHA settings for the project.
2. Authentication: Your server must be authenticated to Google Cloud. The easiest way is to set the GOOGLE_APPLICATION_CREDENTIALS environment variable pointing to a downloaded Service Account JSON key.
3. IAM Roles: The authenticated Service Account requires the reCAPTCHA Enterprise Agent (roles/recaptchaenterprise.agent) role to create and annotate assessments. During the execution of this agent skill, roles/logging.viewer is required so that the skill can automatically validate the success of implementation.
4. Environment Separation: Create two reCAPTCHA keys: one for Test (allowed domains: localhost, 127.0.0.1) and one for Prod (your real domain). Map these to environment variables (e.g., RECAPTCHA_SITE_KEY_TEST and RECAPTCHA_SITE_KEY_PROD) to avoid "Invalid Domain" errors during development.
5. Node.js Dependencies: Run npm install @google-cloud/recaptcha-enterprise to install the required client library.

Workflows

1. Integrate reCAPTCHA

First check if the user is using a V3 key. This skill so far only supports the V3 integration.

Codebase Survey: Passively inspect the user's codebase and dependencies (package.json, environment files, structure) to understand: 1. Frontend Framework: React, Vue, Angular, or Vanilla JS? 2. State Management: How is form state handled? 3. Entry Point: Where is the best place to inject the <script> tag? 4. Secrets Management: Determine how the backend application manages secrets (e.g., .env, Secret Manager). Adapt the secret loading when injecting the integration logic to match this pattern.

Then use v3.md to understand common integration gotchas.

Action: Read the text in assets/frontend-snippets.html and assets/frontend-snippets.js. Instruction: Inject those snippets directly into the user's existing frontend code, adapting them on the fly to match the discovered Framework and State Management patterns.

2. Integrate Transaction Protection (Best Practice: Multi-Stage)

Protecting a transaction is most effective when done in two stages:

1. Stage 1: Initial Frontend Assessment: Collect the reCAPTCHA token on the frontend (using enterprise.js) and send it to your backend. Perform a createAssessment with the token and user identifiers (email). Block bots and high-risk requests immediately.
2. Stage 2: Post-Authorization Enriched Assessment: Use a Payment Service Provider (PSP) like Stripe with manual capture. After the user authorizes the payment, use the webhook to retrieve real card data (last 4 digits, billing zip). Perform a second createAssessment with this enriched data to catch "stolen instrument" fraud before capturing funds.

Codebase Survey (Database & Architecture): You must store the assessmentName or reCAPTCHA token to close the loop later. 1. Architecture Check: Is the payment processing in the same service as the frontend serving? If separated (Microservices), ensure you identify how to pass the transactionId across the boundary. 2. Schema Check: Identify the Database Schema and ORM (e.g., Prisma, Sequoia, TypeORM). * CRITICAL: assessmentName can be long. Use VARCHAR(255) or TEXT. Converting it to a standard UUID column (36 chars) will cause truncation and failures. 3. Mapping Strategy: Determine where to store the transactionId <-> assessmentName mapping.

CRITICAL WARNING: Token Storage Do NOT store the reCAPTCHA token in Stripe's metadata field. The token is often larger than 2000 characters, which exceeds Stripe's 500-character limit for metadata values, causing the request to fail.

Solution: 1. Generate a unique transactionId on your server. 2. Store the token in a server-side store (e.g., Redis, Database, or in-memory map) using the transactionId as the key. 3. Pass only the transactionId in the Stripe metadata. 4. In your webhook, retrieve the token using the transactionId from the metadata.

Reference: See recaptcha-api.md for request/response schemas and the expectedAction requirement.

Action: Read assets/recaptcha-integration.js and generate an equivalent Node.js integration within the user's backend codebase.

Note: The template uses placeholders (e.g., 'YOUR_PROJECT_ID'). You must manually wire these to the user's environment variables (e.g., process.env.CLOUD_PROJECT_ID).

Wiring: 1. Import the generated recaptcha-integration.js in your payment processing route. 2. Call createAssessment before authorizing the charge with your PSP.

Best Practice: Adopt a Fail Open strategy. If the reCAPTCHA API fails or returns an error (other than a fraudulent verdict), allow the transaction to proceed to avoid blocking legitimate users during outages. (The generated code includes a try/catch block for this purpose).

3. Automate Ground Truth & Feedback Loop

The reCAPTCHA model improves when you provide feedback:

1. Annotate: When a transaction is confirmed as legitimate or fraudulent (e.g., via a chargeback), call annotateAssessment.
2. Webhooks: Map PSP events (like Stripe's charge.dispute.created) to the original reCAPTCHA assessment name.

Reference: See psp-webhooks.md for PSP-specific webhook handling.

Action: Determine if the user is using stripe or adyen by reading package.json. Read the corresponding template (assets/webhook-stripe.js or assets/webhook-adyen.js) and inject the endpoint into their backend.

Note: If neither are detected directly in package.json (e.g., wrapped via another library), look for imports or environment variables containing "Stripe", "Adyen", or "Payment" to identify the integration point manually before proceeding.

4. Verify Integration Health & End-to-End Test

Step 1: Metric Check To confirm that your keys are active and receiving traffic, query the reCAPTCHA Enterprise API for metrics. Action: Read assets/check-status.js. Create this script temporarily in their workspace and execute it via node (ensuring environment variables are populated). Review the outputs and delete the script.

Step 2: Logic Verification (Unit Test) Verify your integration logic handles good, bad, and invalid tokens correctly without needing real traffic. Action: Read assets/verify-logic.js. Create a temporary verification script with the contents in the user's workspace, modifying the require('./recaptcha-integration') line to match wherever you injected the integration module in the previous step. Execute it via node, then delete it. This checks the createAssessment function against various scenarios (high score, low score, wrong action).

Step 3: End-to-End Transaction Test (Mandatory) Do not consider the task complete until you have verified the full flow: 1. Frontend: Load the page, check browser console for reCAPTCHA token generation. 2. Backend: Process a test transaction (e.g., using Stripe Test Mode card numbers). 3. Logs: Check server logs to confirm createAssessment was called and returned a verdict. 4. Webhook (Optional): Trigger a test dispute in the PSP dashboard and verify your webhook receives it.

Resources

• API Documentation: recaptcha-api.md
• PSP Webhooks Guide: psp-webhooks.md
• Integration Asset: assets/recaptcha-integration.js
• Frontend Assets: assets/frontend-snippets.html, assets/frontend-snippets.js
• Verification Asset: assets/verify-logic.js
• Webhook Assets: assets/webhook-stripe.js, assets/webhook-adyen.js
• Status Check Asset: assets/check-status.js