The method
A wrong price on a public page is worse than no page. Here is exactly how the record is kept — including the parts a human still has to check.
The record right now
COUNTED FROM THE DATABASE THAT SERVES THIS PAGE · LAST PUBLISHED CHANGE EFFECTIVE 2026-08-13. THE REVIEW QUEUE IS PUBLISHED BECAUSE PENDING WORK IS PART OF THE TRUTH.
The pipeline
Machines checking machines — and when they disagree, or a number moves absurdly far, the line stops and a person decides.
MarkupBot fetches each tracked pricing page on an adaptive schedule — recently changed pages several times a day, quiet ones weekly. A plain fetch first; a real browser only when the page demands it. robots.txt is honoured and nothing behind a login is ever collected — see /bot.
Every capture that differs from the last one is stored raw — the page text and a rendered image, hashed and immutable. Published figures link to the exact capture they came from, so anyone can check the source we saw.
A language model reads the capture into structured plans. Then the machine checks the machine: every extracted price must appear verbatim in the page text, or the whole extraction is discarded. Models suggest; evidence decides.
Yesterday’s plans against today’s, field by field: price, billing interval, seat minimums, included units, limits, features that moved tier. The diff is deterministic code, not model output, and a suite of golden test cases referees every change to it.
Two machines must agree before anything ambiguous publishes: a second, independent model re-reads the capture and audits the first extraction figure by figure. Agreement publishes, contradiction rejects, and anything either side is unsure about — plus every price move beyond ±200% — waits for a human. The queue size is published above.
Changes go live with an effective date labelled either “stated by vendor” or “detected by us” — never implied precision. Alerts fan out the same day. A published change is never silently edited; fixes go through public corrections.
Provenance
These are the three tags you'll find beside numbers across the site — the same ones shown here.
The figure comes from one of our own archived captures. The tag links to the capture itself — the page as it looked the day the price changed.
History from before we tracked a product, rebuilt from vendor announcements, changelogs and public archives — linked to the announcement, never blurred with our own captures.
A figure that went through the public corrections process. The note says what was wrong, who caught it, and when — every one is published at /corrections.
House rules