Price methodology

The repository contains a 200-variant candidate queue and empty shadow exports. It does not currently publish live market claims.

Exact identity first

An offer must resolve to an exact manufacturer variant. A strong GTIN, MPN, or reviewed retailer mapping can identify a candidate, but a conflict in category-specific blocking attributes always rejects it.

Current comparison

A comparison offer may appear only when its source policy permits current display and cross-retailer comparison. Comparable total is item price plus mandatory shipping, before tax. Condition, seller, stock, restrictions, and observation time remain visible.

Representative category indices

For each exact variant and day, the reference price is the median of at least two independent, index-eligible origin offers. Category indices chain weighted geometric means of matched price relatives with a base value of 100. A daily point is suppressed below 80% basket-weight coverage or when freshness, concentration, compliance, or quality gates fail. New and used asking prices are never blended.

Launch gate

Sample mode remains mandatory until two independent sources permit durable observations and public derivatives, exact-match precision is at least 99%, link health is at least 95%, correction rate stays below 1%, weighted coverage reaches 80%, and 30 consecutive shadow closes are clean.