Competitor price monitor

Monitor competitor-site prices and send alerts when they change.

When to use it

Tens to a few hundred SKUs on pages with stable markup. Past a thousand SKUs, prefer an official API or a data vendor.

Flow

Steps

1. Load list — read the product URLs to watch
2. Extract — read the price, handling both sale and struck-through prices
3. Compare — diff against the previous snapshot and compute the delta
4. Alert — push to Feishu or email once the threshold is crossed
5. Record — always store a snapshot, alert or not, so the trend stays auditable

Options

Option	Description	Default
urls	Product page URLs	required
selector	Price element selector	auto-detected
threshold	Relative change that triggers an alert	0.05
schedule	Check frequency	0 */6 * * *
notify	Alert channel	feishu

Snapshot

{
  "url": "https://example.com/p/1001",
  "price": 299.0,
  "currency": "CNY",
  "previous": 329.0,
  "change": -0.0912,
  "checked_at": "2026-08-11T06:00:00+08:00"
}

Where price extraction breaks

Sale periods insert extra price elements — list price, final price, price-after-coupon. Auto-detection picks the primary displayed price; during big sales, set selector explicitly and spot-check the results.