Every public comparison needs a traceable product and offer.

Last updated: September 14, 2026

This page separates two kinds of PriceFlock work. Data methodology governs how provider records become products, offers, availability labels, and price history. Editorial methodology governs how shopping guides explain useful comparison decisions without pretending that PriceFlock physically tested a product.

Authorized provider source data

Public catalog information begins with an authorized provider source: an official retailer API, approved affiliate-network feed, or other catalog supplied with permission for the comparison use case. Credentials alone do not establish that permission. A provider remains disabled until both technical access and the necessary commercial or written authorization are in place.

The source can supply product identifiers, brand, model, title, category, image URL, item price, currency, availability, merchant name, destination URL, shipping data, and timestamps. PriceFlock normalizes fields needed for browsing and comparison but does not invent a missing price, GTIN, specification, stock state, image, or retailer relationship. Retailer pages are not scraped to fill missing feed records.

Exact GTIN comparison

GTIN-8, GTIN-12, GTIN-13, and GTIN-14 values must contain the correct check digit before PriceFlock uses them as shared product identity. A valid GTIN is normalized as an exact sequence of digits, including meaningful leading zeroes. Offers are not united by similar titles, photos, or marketing language.

A public exact GTIN comparison requires offers from more than one distinct normalized merchant. For the product detail page, PriceFlock keeps the lowest eligible current offer from each merchant and sorts the retained offers by price. Duplicate rows from one merchant do not inflate the store count. Savings is the difference between the lowest and highest retained merchant prices. GTIN-less products remain separate under their existing provider identity rather than receiving an unsupported exact-match claim.

What “Last checked” means

“Last checked” is the readable form of the offer’s observed_at value. It tells the shopper when PriceFlock recorded that provider offer. It does not mean the item is reserved, and it does not guarantee that the retailer’s price, shipping, or stock will remain unchanged after that time.

Observation age does not hide an active offer. It is separate from catalog membership and source availability. An older timestamp does not by itself prove that an approved active-catalog offer was removed. PriceFlock uses the provider’s active status, accepted availability and condition, source authorization, and public visibility rules to decide whether an offer remains in shopping surfaces.

How price history is formed

Price history consists only of verified price observations already recorded for the same product identity and currency. The chart shows a bounded set of recent points so it remains readable, while historical low and high calculations use the available comparable history. A first observation may produce a current price without enough points for a meaningful chart.

History describes what PriceFlock observed; it does not predict a future sale, establish a product’s permanent market value, or promise that an earlier price will return. A sudden difference can reflect a new offer, bundle, variant, source correction, or merchant change, so exact identity remains necessary when interpreting the chart.

Availability and out-of-stock records

Current in-stock offers can appear in active catalog, search, category, and comparison surfaces. When no active offer remains, the product is removed from those active shopping surfaces and from the public product sitemap. Its product record may remain to preserve the last verified image, price history, favorites, and alerts. If availability returns through an authorized source, the same product can re-enter the catalog without discarding those relationships.

Price summary and ranking

The product page calculates its current lowest and highest eligible item prices from the retained offers. Where multiple distinct merchants exist, it can show the difference between those prices. Known shipping may be shown separately, but taxes, location restrictions, memberships, subscriptions, and checkout-specific charges must be confirmed with the retailer.

Catalog surfaces share a global quality ranking. Anonymous browser-side interests may add relevance without replacing that shared ranking or sending a personal shopping profile to the server. Affiliate commission rates do not create an exact match or override the source and identity rules.

Editorial guide standards

PriceFlock guides are original publisher content written to help shoppers compare exact models, sizes, formats, included items, compatibility, and retailer terms. Merchant descriptions are not republished as independent editorial work. A guide does not claim that PriceFlock tested, wore, installed, tasted, or used a product unless that work has actually occurred and the method is stated.

Guides may explain how to use current offers, availability, observed timestamps, and available price history. They do not turn a retailer claim into a verified editorial conclusion. Corrections can be submitted through Contact. For the simpler shopper-facing sequence, read How PriceFlock Works.