How this is measured

A pricing page is a moving target that nobody archives. This site exists because the only way to know what something cost last month is to have looked last month.

What happens each day

Every one of the 133 tracked pricing pages is fetched once daily. Pages that render prices in JavaScript are loaded in a real browser. The price-bearing lines are extracted, hashed, and compared with the previous day's. A difference is stored with both versions intact.

What counts as a change

Only a movement in a figure a customer would be charged. Vendors rewrite marketing copy constantly, and an early version of this tracker published several "price changes" that were nothing of the kind — a funding announcement read as a plan price, a currency display switching from yen to dollars because of a header we ourselves had changed. Those cases are now regression tests that run before anything is published.

When the tracker itself moves

The most dangerous error this project can make is to report its own instrumentation as somebody else's price change. Companies do not reprice in unison, so any date where a large share of the tracked set appears to move at once is treated as a change in the measurement, not the market — and the comparable record restarts from that date.

Dates currently excluded on this basis: 2026-08-16.

What we do not do

We do not estimate, interpolate, or reconstruct prices from before we started watching. The record begins on the day it begins: August 15, 2026, 25 days of observation so far. Where a page defeats extraction, the page says so rather than showing a guess.

Corrections

Every figure links to the source page and the date it was read. If a number here disagrees with the vendor's page, the vendor's page is right and we want to know.