Every dot needs a source.

1. Identify the exact product

We maintain a canonical product record independently from retailer listings. GTINs, model numbers and retailer product codes are retained with their source, observation time and validation outcome.

2. Match retailer offers conservatively

An offer is attached only when identifier or exact-model evidence is strong enough. Ambiguous evidence is rejected or queued for review.

3. Append observations

A successful collection records the observed item price, delivery price when known, availability, currency, retailer, source and timestamp. Money is stored in integer pence.

4. Preserve gaps and failures

A failed collection run is stored separately and leaves the last successful observation unchanged. Out-of-stock status requires evidence from a successful collection.

5. Make recommendations only when justified

One observation establishes a starting point. Trends, historical lows and recommendations require a larger body of genuine observations.

Current coverage

The initial catalogue contains exact portable air-conditioner models. Its first Currys observations were manually reconciled from the supplied project research. Each was out of stock when initially observed. Current pages derive availability from the latest successful observation.