HALOWERK Price History Median Drop Detector

Choose this endpoint when you have a structured price history series (at least 3 observations) for a specific product URL and need to compute the historical median and programmatically detect whether a price drop of a given magnitude has occurred. It is particularly useful in automated deal-detection pipelines, repricing validation workflows, and price-alert systems where you want a statistically grounded drop signal rather than a simple point-to-point comparison. Prefer it over simple delta comparisons when you need median-based robustness against price outliers.

• Fewer than 3 history items supplied — minimum minItems:3 validation error
• Currency code not matching 3-letter ISO format — pattern validation failure
• Observed_at timestamps malformed or too long (>40 chars)
• Price values exceeding maximum of 1,000,000,000 or negative — schema validation error
• drop_percent set to 0 or negative — exclusiveMinimum violation
• Idempotency key too short (<32 chars) or contains invalid characters
• Payment not provided or insufficient USDC on Base Mainnet — HTTP 402 response
• callback_url unreachable or malformed — async delivery failure