Fire Tablet Intercom

Local-only WebRTC audio intercom for Fire tablets. Next.js + Tailwind (client) and Socket.io signaling (server). Tablets hit http://LXC_IP:3000/intercom. FYI, if we are talking code, we are likely on my macos env for dev. Code is deployed via git to remote LXC on my LAN.

Setup Summary: A WebRTC audio intercom for Fire tablets: Next.js 16 (App Router) + React 19 + Tailwind CSS 4 client (client/ui) and an Express + Socket.io signaling server (server). Development runs on macOS (UI on 3000, signaling on 3001); production deploys to Proxmox LXC containers (Debian 12/13) via setup-lxc.sh, which installs Node.js LTS, builds the Next.js app, configures environment variables (NEXT_PUBLIC_SIGNALING_URL), and runs both services under pm2 with systemd integration. The client uses WebRTC peer connections (Google STUN) with Socket.io signaling, Web Audio API highpass filtering, push-to-talk controls, and connection state monitoring. Tablets access http://LXC_IP:3000/intercom; optional Caddy HTTPS proxy supports macOS/iOS testing. The codebase uses TypeScript, minimal dependencies, and a monorepo structure with separate client/server packages.

Prereqs

• Node 20+ (Nodesource LTS repo is fine).
• npm.
• Git.

Workflow

1. Develop on macOS: Edit code locally, test with npm run dev.
2. Push to GitHub: git push origin main (or your branch).
3. Deploy on LXC: Clone from GitHub and run setup-lxc.sh.

Local dev (macOS)

cd /Users/chase/Code/intercom
cp client/ui/env.example client/ui/.env.local        # set NEXT_PUBLIC_SIGNALING_URL to http://localhost:3001
npm --prefix server install
npm --prefix client/ui install
npm --prefix server run dev   # port 3001
npm --prefix client/ui run dev # port 3000
# browser: http://localhost:3000/intercom

Environment

• Client .env.local:
  • NEXT_PUBLIC_SIGNALING_URL=http://LXC_IP:3001
• Server env (pm2/systemd):
  • PORT=3001
  • ALLOWED_ORIGINS=http://LXC_IP:3000

Proxmox LXC deploy (Debian 12/13)

1. Create LXC using community-scripts helper:

   bash -c "$(curl -fsSL https://raw.githubusercontent.com/community-scripts/ProxmoxVE/main/ct/debian.sh)"

   Choose Debian 12 or 13, unprivileged, static LAN IP, 1 vCPU, 1–2GB RAM, 15–20GB disk.

2. Inside LXC (as root):

   export LXC_IP=192.168.4.226  # your LXC's LAN IP
   
   # Install git if not present (script will install node/pm2)
   apt update && apt install -y git
   
   git clone https://github.com/chasecee/intercom.git /opt/intercom
   cd /opt/intercom
   chmod +x setup-lxc.sh
   ./setup-lxc.sh

The script installs Node.js/pm2, installs deps, builds Next.js, creates .env.local, and starts both services with pm2.

Update/redeploy

After pushing changes from macOS:

# On LXC
cd /opt/intercom
git pull
./deploy.sh

The deploy script will:

1. Install server dependencies (npm ci in server/)
2. Install client dependencies (npm ci in client/ui/)
3. Build the client application (npm run build)
4. Restart both pm2 services (intercom-signal and intercom-ui)

For manual deployment:

cd /opt/intercom
git pull
cd server && npm ci && cd ..
cd client/ui && npm ci && npm run build && cd ../..
pm2 restart intercom-signal
pm2 restart intercom-ui

Reset/redeploy

pm2 delete all
rm -rf /opt/intercom
git clone https://github.com/chasecee/intercom.git /opt/intercom
cd /opt/intercom
export LXC_IP=192.168.4.226
./setup-lxc.sh

Tablets

• URL: http://LXC_IP:3000/intercom (or https:// if you set up Caddy below)
• Keep screen on, kiosk mode, auto-reload in Fully Kiosk.

HTTPS setup (for macOS/iOS testing)

macOS Safari/Chrome and iOS Safari block getUserMedia on HTTP for non-localhost URLs. Fire tablets (Android) work fine with HTTP, but if testing on macOS/iOS, use HTTPS. Browsers also block mixed content (HTTPS page connecting to HTTP WebSocket), so we proxy signaling through HTTPS too.

# On LXC, install Caddy
apt install -y debian-keyring debian-archive-keyring apt-transport-https gnupg
mkdir -p /etc/apt/keyrings
curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/gpg.key' | gpg --dearmor -o /etc/apt/keyrings/caddy-stable.gpg
echo "deb [signed-by=/etc/apt/keyrings/caddy-stable.gpg] https://dl.cloudsmith.io/public/caddy/stable/deb/debian any-version main" >/etc/apt/sources.list.d/caddy-stable.list
apt update && apt install -y caddy

# Create Caddyfile (proxy Socket.io WebSocket through HTTPS)
# Replace 192.168.4.226 with your LXC_IP
cat >/etc/caddy/Caddyfile <<EOF
192.168.4.226 {
  reverse_proxy /socket.io/* localhost:3001
  reverse_proxy /intercom* localhost:3000
  reverse_proxy /_next/* localhost:3000
  reverse_proxy / localhost:3000
  tls internal
}
EOF

# Update UI env to use HTTPS (no port, Caddy proxies /socket.io/*)
# Replace 192.168.4.226 with your LXC_IP
cat >/opt/intercom/client/ui/.env.local <<EOF
NEXT_PUBLIC_SIGNALING_URL=https://192.168.4.226
EOF

# Update server CORS to allow HTTPS origin
# Replace 192.168.4.226 with your LXC_IP
pm2 delete intercom-signal
cd /opt/intercom/server
PORT=3001 ALLOWED_ORIGINS=https://192.168.4.226 pm2 start npm --name intercom-signal -- run start
pm2 save

# Rebuild UI with new env
cd /opt/intercom/client/ui
npm run build
pm2 restart intercom-ui

# Start Caddy
systemctl enable caddy
systemctl start caddy

# Verify Caddy is listening on 443
ss -tlnp | grep caddy

Then access https://192.168.4.226/intercom. Browsers will show a security warning about the self-signed certificate (Caddy's tls internal); click "Advanced" → "Proceed" to accept it. No certificate copying needed—this is all server-side.

Note: The signaling WebSocket is proxied through Caddy on HTTPS (wss://), so both UI and signaling use HTTPS. For Fire tablets, HTTP works fine (no HTTPS needed).

Troubleshooting

Check service status:

pm2 ls
pm2 logs intercom-signal --lines 50
pm2 logs intercom-ui --lines 50

Test signaling server:

curl http://localhost:3001/health  # should return {"status":"ok"}

Test UI locally (macOS) connecting to LXC signaling:

# On macOS, update local .env.local to point to LXC
cd /Users/chase/Code/intercom/client/ui
cat >.env.local <<EOF
NEXT_PUBLIC_SIGNALING_URL=http://192.168.4.226:3001
EOF
npm run dev
# Then access http://localhost:3000/intercom

Caddy not starting:

• Check Caddyfile syntax: caddy validate --config /etc/caddy/Caddyfile
• Check logs: journalctl -u caddy -n 50
• Verify ports: ss -tlnp | grep caddy (should show 80 and 443)

WebSocket not connecting:

• Ensure Caddyfile proxies /socket.io/* to localhost:3001
• Check CORS allows the correct origin
• Verify signaling URL in .env.local matches your setup (HTTP vs HTTPS)

Services not starting after reboot:

# Check if pm2 systemd service exists
systemctl status pm2-root

# If not configured, set it up:
pm2 startup
# Then run the command it outputs (as root)

# Or manually start services:
pm2 resurrect
pm2 save

# Verify services are running:
pm2 ls
pm2 logs