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HALOWERK Article Price Percentage Drop Detector
x402
HALOWERK Article Price Percentage Drop Detector is a paid API for AI agents from handel.halowerk.com, paid per call via x402, $0.007/call, status unknown (last checked 2026-10-10).
Fetches a product article's current price from a URL and calculates whether it has dropped by a specified percentage compared to a previously known price
Price / call$0.007
Success—
StatusUnknown
How this service works
Notify when a listed-price reduction reaches a chosen percentage; previous price must be positive. Uses an optional predicate extension of the proven Price-Callback motor. price_percentage_drop_decision records this exact rule; the rule executes BEFORE dispatch. Same public IPv4HTTPS pinned connections, robots checks,9s,1MiBHTML,at-most-once receipt/idempotency7days,failureschargedfalse. Caller supplies historical price and schedules polling.
Output
A JSON response indicating whether the article's current price has dropped by the specified percentage relative to the provided previous price, likely including the current price, the calculated drop percentage, and a boolean or signal confirming whether the threshold was met.
Example use cases
Flash sale price drop alert
“The product at https://www.store.com/items/blue-jacket was 120.00 EUR last week — has it dropped by at least 20% since then? Check it now.”
Competitor price monitoring
“I previously saw this competitor article at https://competitor.com/products/widget priced at 45.50 USD. Tell me if it has dropped by 10% or more.”
Deal validation before purchase
“Before I buy, check if https://retailer.com/en/product/headphones has gone down by at least 25% from the 199.99 GBP price I recorded last month.”
Technical details
Endpoint
POSThttps://handel.halowerk.com/v1/price/articles/percentage-drop?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to programmatically detect price drops on specific article URLs against a previously known price and percentage threshold — especially in automated deal-detection pipelines, price alert workflows, or shopping agents. Prefer this over generic scraping when you want a structured, paid-per-call service with idempotency support and optional callback for async notification.
Side effects
- URL is unreachable or returns non-200 response — endpoint may return an error or empty result
- Article page does not contain a parseable price — extraction fails
- Currency mismatch between previous price and current scraped price
- drop_percent must be greater than 0 and at most 100 — validation error if out of range
- previous.value must be between 0 and 1,000,000,000 — error if exceeded
- idempotency_key too short (min 32 chars) or contains invalid characters
- Payment failure via x402 protocol prevents request from being processed
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| url | string | |
| previous | object | |
| callback_url | string | |
| drop_percent | number | |
| idempotency_key | string |
Output
Schema · Response
{
"type": "json"
}Tags
x402
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