Methodology: where prices come from and how we compute them

Sources

We only collect price lists that merchants and service providers publish in a machine-readable format (CSV, XML, JSON) under NN 101/26: a separate file for each store or venue. Every source is tied to the legal entity's OIB, and every store to the code the merchant assigns to it.

Frequency

Every source is checked at least once a day; large chains and online shops up to three times a day. Each downloaded file is stored with its date and a SHA-256 checksum, so the same file is never imported twice and every record can be traced back to its source file.

Products and barcodes

Products are identified by their EAN/GTIN barcode after the check digit is verified. In-store barcodes (scales, prefix 2) are not global and are never matched across merchants. A product without a valid barcode is keyed merchant:product code.

Price history

We store the price state per product and store: retail price, unit price, regular price, lowest price in 30 days, anchor price, special sale and availability. A new history record is written only when one of these values changes, with the date it applies from. This gives the exact state for any day since 10 Sep 2026.

Lowest price in 30 days

We show two values: the one the merchant states and the one we compute from the history. A difference between them is information for the user, not a correction of the merchant's data.

Anchor price

The anchor price is the price on a reference date: 2 May 2025 for food, drinks, cosmetics and household products, and 10 Sep 2026 for all other goods and services. Every anchor price is shown with its date.

Medians and aggregates

• For a service in a city we compute the lowest, median and highest price among places with a public price list.
• A page is opened to search engines only once prices from at least 3 different places exist; smaller samples are shown but not indexed.
• The median is robust against individual extreme prices, so we use it instead of the average.
• Every aggregate shows the number of places and the date of the last refresh.

Limitations and corrections

price.download is not an official source. If the data in the original price list is wrong, the merchant has to correct it. If we collected or matched a record incorrectly, let us know through the contact page or the “Report an error” button next to the record.