emailrules.today

Mailbox providers · verified 4 Aug 2026

What they actually said. And what they never did.

Nobody outside Google knows how Gmail filters mail, and every page claiming to explain the algorithm is either restating the published guidelines or inventing. So this does the opposite. For each provider: the requirements and numbers it printed, in its own words — and, given the same weight, the things this industry repeats that the provider has never said anywhere.

5providers
12verbatim quotes
9claims nobody made
4/5sources printing no date

That last figure is the uncomfortable one and it stays on the page. Google’s help centre and Yahoo’s sender hub print no publication date on the pages that carry their requirements, so none is claimed here. A reference that invents a plausible date to look rigorous has stopped being one.

Opened, with nothing to publish

These were looked at during this review and produced nothing that met the bar. The reason matters more than the absence, so each one says why. A delisting path published from memory is how a reference gets somebody’s mail permanently blocked.

  • Proton MailPublishes user-facing help and a security policy, but no sender guidance, no thresholds and no delisting path we could cite. Nothing to put in a threshold column.
  • GMX and Web.deUnited Internet operates a postmaster contact, and the sender documentation behind it is not published as a stable, dateable page in English or German. Watched.
  • Mail.ru, Yandex, QQ, NetEase, Naver, DaumEach runs a real postmaster function with real delisting. None has been read against this corpus's bar yet, and publishing a delisting path from memory is precisely how a reference gets somebody's mail permanently blocked.
  • Comcast, Cox, Charter and the US cable ISPsMostly delegate consumer mail to third-party filters now, so the question is usually which filter rather than which ISP. Not yet traced to a citable page per operator.

A provider missing, a quote wrong, or a delisting path that has moved? corrections@emailrules.today. How a claim gets onto this site at all is on methodology; the same discipline applied to blocklists is the census. Last verified 4 Aug 2026.

FAQ

Awkward questions

Who is this actually for?

People who ship email and are too busy to re-read every PDF: week-one marketers, lifecycle/CRM, deliverability, multi-country ops, DTC brands, agencies — on Klaviyo, Mailchimp, Braze, HubSpot, SFMC, or something else. Pick your tool and geos so product-specific pages only appear when they match. EU and UK are first-class filters. Not for people who sell tools about email and need a fake score to demo.

Why only ~40 rules? Isn’t that… thin?

On purpose. A wall of 400 undated “best practices” is how you look busy and still get burned. Every page needs a primary source we actually read. Thin and checkable beats fat and folklore. Europe, bulk inbox rules, measurement honesty, and protocol topics like BIMI/DMARC policy are on the shelf when we can cite them — not every Member State and not every vendor myth. Coverage map lists what we still refuse to invent.

Is this legal advice?

No. If it were, you’d have a billable hour and a longer PDF. This is a dated operator reference written by an email geek. Confirm anything high-stakes with counsel who knows your facts. Same for “will this make me compliant?” — no tool does that. Lawyers and judges do. We say what the sources say and what to do first on Monday.

Why no trust score out of 100?

Because we refuse to invent a number you can’t audit. Fake scores sell seed tests and panic. You get findings, dates, and links. If that feels less exciting than a red dial, good — you’re not the red-dial customer.

Why should I trust you more than my ESP’s blog?

ESPs sell seats. Seed-score vendors sell fear. AI invents citations when nobody watches. We sell nothing today — no pixels, no placement scores, no affiliate — so we can say when a tool is the problem. A human verifies, dates, and corrects in public. Tools may help draft; they do not ship unsourced claims. Check the primary links. Fail that test and leave.

Do I need an account?

No. Filters live in this browser and the URL. Share the link. That’s it. Accounts come later only if they earn it — not so we can nurture you about email.

I’m an agency. Where’s multi-client mode?

We tried a client-name CRM on the setup card. It made the product feel like work before it felt useful. Role filters + copy link + one-page brief (optional PDF title) is enough for now. Complexity comes back when the free shelf is habit, not before.

Is the quiet changelog a bug?

No. Quiet means nothing material moved. We don’t invent urgency so the homepage looks “alive.” Sticky risks still show what usually needs a person when the market is still.