How we make and check this site

An AI model reads the official sources, writes our pages and does the math. Scripts then check the pages against our data files before an update goes live. A full-time reseller owns and runs the site. This page says how each step works; every count on it is read from our data files when the site is built.

Sources we use, and the ones we don't

Our sources are the organizations' own pages: USPS (Postal Explorer's price list and Domestic Mail Manual, usps.com and the USPS newsroom), the Postal Regulatory Commission, the Federal Register, the eCFR and other government sites, the IRS, the FTC, state revenue departments and legislatures, and each platform's or company's own fee, help and pricing pages and announcements. For past years that USPS's own pages no longer show, we link an archived copy of the USPS page.

• eBay and Amazon: we link their pages but never fetch them. Their numbers come only from dated copies of their public pages saved in our evidence files. The copies in use today were saved on Oct 14, 2026, before we stopped reading those sites ourselves; from now on, new copies come only from the owner, saved by hand in his own browser.
• Sites that block automated readers: the help centers of Depop, Whatnot and Etsy (whose fees our calculators use), and of Reverb, Discogs, Bonanza and Shopify, show our checker a challenge page instead of the article, and so does EUR-Lex, the EU's law site. Some state tax and agency pages refuse it too, or ask AI crawlers not to visit. We don't work around a block: no other address, copy, archive or user agent, and no automated browser. Figures that rest on those pages show the day we last read them, and wait for the owner to check them by hand in a normal browser.

How a number gets on a page

• We save dated copies of the source pages we read, and for many we also record a cryptographic fingerprint (a hash) of the file, so a later change to a copy would show.
• Prices and fees are kept in data files (USPS prices, platform fees and the change tracker each have their own), which the pages, the calculators and our data feeds read when the site is built. Where a page states one of the key prices, fees or dates in its own words, the fact gate below checks it against the data file.
• Quotes are kept short and in quotation marks. On our USPS pages and most fee and reference pages, tests match each quote word for word against the saved copy of its source; our tax and law pages aren't covered by that check yet.

What runs before every update

Our deploy command runs these checks first and stops if any of them fails:

• The test suite, once before the site is built and again on the built pages.
• The build checks: every page has its title, description, AI disclosure and structured data that parses; no internal link is broken; every page we ask search engines to index can be reached from the home page; and no private detail about the owner and no Amazon or eBay affiliate link appears anywhere in the output. The plain-text copy of each page must say what the page says: the same headings, every dollar and percent figure, and no extra words.
• The fact gate: 88 facts (prices, fees, thresholds and dates) stated on the pages Google shows most often, each read from its data file. It reads every page, every plain-text copy and our llms.txt files for AI assistants, and fails on a statement that contradicts the data, an old price stated as current, a time-limited price still shown after it ended, or new prices shown before they take effect. The 7 facts that rest on blocked help centers only warn until the owner checks them.
• The near-duplicate gate: each page we ask search engines to index is compared with the other pages built from the same template. A page fails when its 5-word sequences match a sibling's at a similarity of 0.7 or more, or when fewer than 100 of its words are its own.
• The link gate: every page we ask search engines to index, other than the home page, needs links from the main text of at least 3 other pages, and must be no more than 3 clicks from the home page.
• The Toolkit check: the spreadsheet we sell must be built from the same fee and postage data as the site.

Pages that already failed the two gates when they started on Oct 28, 2026 are on a list with a fix-by date (26 entries today). The list can only shrink: a page can leave it, but no new failure can join it.

How pages are written

Why an AI model: one person owns and runs the site, and the work is close reading of official documents and keeping the same figures right on many pages, which a model does quickly. A model can also get facts wrong, which is why the checks above run before every update.

Since our release batch of Oct 19, 2026, each new batch of pages has gone through three separate AI passes: one builds the pages from the official sources and saves a copy of each, a second reviews them, and a third audits the work against the record of what the first two actually read and ran, not against their own reports. Pages from before that batch, and some single pages and tracker entries added since, didn't all get three passes. The checks above run on every page.

What a person does today

• A full-time reseller owns and runs the site.
• No page has had a person's review yet. When the owner reads a page and checks it, that page will say so under its title, with the date, and this page will list it.
• The pages our checker can't read are on a list of hand checks for the owner: open each in a normal browser, logged out, and tell us "ok" or what changed. Until he does, the figures that rest on them show the day we last read them.
• Once the newsletter starts, he edits every issue before it goes out.

Calculators

The 8 fee calculators read each platform's published rates from the same data file as our comparison pages and our fees data feed, and each one explains its method in its own "How ... calculates" section. The postage calculator reads the USPS price files and explains itself under "How the calculator prices a package"; the minimum-price calculator shows "The formula". The calculators run on code with automated tests. The tax calculators are general information, not tax advice: check with a tax professional about your own situation.

What the dates mean

• Updated, in the line under a content page's title ("By The Reseller Index · AI-drafted from official sources · Updated ..."), is the day the page's main text last changed. The same date is the page's dateModified in its structured data, its lastmod in our sitemap and last_updated in its plain-text copy. Re-reading a source that still says the same thing doesn't change it, and neither do sign-up boxes, our own offers or a change to a date alone (a new "checked" date, for example).
• Checked (or "verified on", "last read on") is the day we last compared a page's figures with its sources. A page can be checked often and stay unchanged; we never move a page's updated date to make it look fresh.

Corrections, independence and money

• When we get something wrong, we fix it on the page and log it, dated, on the corrections page. When a source changes, that's an update: the page changes to match it, and a fee, postage, policy or tax change also gets an entry in the change tracker. Under most Sources boxes, a "Report it" link opens the corrections form with that page filled in.
• One person owns the site and pays for it; how it makes money is on the disclosures page. We use no affiliate links. Our own Profit Toolkit is labeled as ours, and sponsors are labeled "Sponsored"; sponsors have no say over the tracker, the calculators or our coverage.
• We're not affiliated with or endorsed by the platforms, carriers or agencies we cover. Who we are and who the site is for: about the site. To reach us: the contact page.