Recipe: Price Drop Alert

Get notified when an e-commerce product drops in price by more than 5%.

POST /v1/monitors

curl -X POST https://api.verid.dev/v1/monitors \
  -H "Authorization: Bearer $VERID_API_KEY" \
  -d '{
    "name": "Nike Air Max Price Alert",
    "url": "https://www.nike.com/t/air-max-90-shoes",
    "schedule_interval_seconds": 3600,
    "extract_config": {
      "method": "css",
      "fields": {
        "price": "[data-test=product-price]",
        "title": "h1"
      }
    },
    "diff_predicate": {
      "type": "field_decreases_by_percent",
      "field": "price",
      "threshold": 5
    },
    "deliveries": [
      { "type": "webhook", "url": "https://your-app.com/hooks/price-drop" }
    ]
  }'

The field_decreases_by_percent predicate only works with numeric values. CSS-extracted prices that include a currency symbol like "$49.99" parse as NaN and will not trigger. Use a site that returns a raw number, switch to JSONPath against the site's product API, or pair with LLM extraction to normalize prices to numbers.

See this pattern applied end to end in Competitor Price Tracking and Shopify product stock & price monitoring.