Facebook Leads Node.js Integration

I already collect leads through Facebook Lead Ads and now need a lightweight Node.js service that listens for every new submission, grabs the full lead details together with several custom fields, and posts them straight into my CRM in real-time. I will supply API credentials for both Facebook and the CRM the moment we start; the solution simply has to accept those values from an .env or similar config file so I can switch keys without touching the code.

Here is what has to happen from end to end:

• The service subscribes to the Facebook Graph webhook for my page, receives the payload instantly, and refreshes the access token automatically when required.
• It parses the lead object, maps each standard field plus the custom fields I specify, and calls the CRM’s REST endpoint with a clean JSON body.
• Any failed push should be retried with exponential back-off and logged to a local file as well as the console.
• A concise README explains setup, environment variables, and how to add or rename field mappings.

Acceptance criteria
1. A new Facebook test lead shows up inside my CRM within 30 seconds.
2. All custom fields arrive with the correct values and labels.
3. Logs clearly distinguish successes from errors and never expose tokens.
4. Code quality: modern JavaScript (ES6+), typed either with JSDoc or TypeScript, lint-clean, and organised in modules I can extend later.

Please package the finished service, the README, and a short video or screenshots proving a live test from Facebook to the CRM.