How do I get an alert when a package has had no scan in X days?

curl -X PUT https://api.lastscanned.com/v1/webhook \
  -H "Authorization: Bearer lsk_live_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"url": "https://example.com/lastscanned"}'
# the response has your signing secret (whsec_...)

curl -X POST https://api.lastscanned.com/v1/watches \
  -H "Authorization: Bearer lsk_live_YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{"trackingNumbers": ["1Z000Y770414233027", "541270563758"], "metadata": {"order": "1042"}}'

// node stale.mjs   (run hourly from cron or any scheduler)
const DAYS = 3;
const cutoff = Date.now() - DAYS * 86400000;
const stale = [];
let cursor = null;
do {
  const url = new URL("https://api.lastscanned.com/v1/watches");
  url.searchParams.set("limit", "200");
  if (cursor) url.searchParams.set("cursor", cursor);
  const res = await fetch(url, { headers: { Authorization: `Bearer ${process.env.LASTSCANNED_KEY}` } });
  const { watches, nextCursor } = await res.json();
  for (const w of watches) {
    const newest = w.result?.events?.[0]; // events are newest first
    const lastScan = newest?.timestamp ?? newest?.localTime ?? null;
    if (Date.parse(lastScan ?? w.createdAt) < cutoff) {
      stale.push({ trackingNumber: w.trackingNumber, carrier: w.carrier, status: w.status, lastScan, metadata: w.metadata });
    }
  }
  cursor = nextCursor;
} while (cursor);
console.log(stale); // send these to Slack, email or your helpdesk

import crypto from "node:crypto";
import express from "express";

const app = express();
app.post("/lastscanned", express.raw({ type: "application/json" }), (req, res) => {
  const { t, v1 } = Object.fromEntries(req.get("Lastscanned-Signature").split(",").map((p) => p.split("=")));
  const expected = crypto.createHmac("sha256", process.env.LASTSCANNED_WHSEC).update(`${t}.${req.body}`).digest("hex");
  if (Math.abs(Date.now() / 1000 - Number(t)) > 300 || !crypto.timingSafeEqual(Buffer.from(v1, "hex"), Buffer.from(expected, "hex"))) {
    return res.sendStatus(401);
  }
  const event = JSON.parse(req.body);
  if (event.type === "tracking.updated" && event.data.result.status === "exception") {
    console.log("exception", event.data.watch.trackingNumber, event.data.result.statusDescription, event.data.watch.metadata);
  }
  res.sendStatus(200); // answer 2xx within 10 seconds
});
app.listen(3000);