FB Group Watcher

A Chrome extension that summarizes Facebook group posts and sends you an email digest.

How it works

The extension uses a visual approach to extract posts from Facebook groups. Instead of parsing Facebook's DOM, it captures screenshots of the page and uses Claude's vision capabilities to identify and extract post content.

Architecture

┌─────────────────────┐         ┌─────────────────────┐
│  Chrome Extension   │  HTTP   │   Vercel Function   │
│  - Capture          │────────▶│   - Extract posts   │
│    screenshots      │         │     (Claude Vision) │
│  - Send to backend  │         │   - Summarize (LLM) │
└─────────────────────┘         │   - Send email      │
                                └─────────────────────┘

The extension captures 3 screenshots while scrolling through the group feed, then sends them to the backend where Claude Vision extracts the posts and summarizes them.

Setup

1. Install dependencies

npm install

2. Deploy to Vercel

npx vercel --prod

3. Configure environment variables

Set these in the Vercel dashboard:

Variable	Description
ANTHROPIC_API_KEY	Claude API key (required)
RESEND_API_KEY	Resend API key (required)
RECIPIENT_EMAIL	Your email address (required)
API_SECRET	Shared secret for API auth (required)
LLM_PROVIDER	claude (default) or openai for summarization
OPENAI_API_KEY	OpenAI API key (only if using openai provider)

4. Configure extension

1. Edit extension/popup.js and set API_URL to your Vercel deployment URL
2. Copy extension/config.example.js to extension/config.js
3. Set API_SECRET in config.js to the same value you used in Vercel. You can generate a secret by running openssl rand -hex 16 for example

cp extension/config.example.js extension/config.js

Note: config.js is gitignored and won't be committed.

5. Add extension icons (optional)

Add these files to extension/:

• icon16.png (16x16)
• icon48.png (48x48)
• icon128.png (128x128)

6. Load the extension

1. Open chrome://extensions
2. Enable "Developer mode"
3. Click "Load unpacked"
4. Select the extension/ folder

Usage

1. Navigate to a Facebook group
2. Click the extension icon
3. Click "Summarize & Email" (the extension will scroll and capture screenshots automatically)
4. Check your inbox (or your spam folder if you don't see the email)

LLM providers

The default provider is Claude (claude), which is required for the vision-based post extraction.

Initially OpenAI (openai) support was planned, but was not built after Facebook DOM parsing proved problematic.