emailrules.today
Stop 2 of 8Week oneThe hour before send

From domain

The domain after @ in the From address people see in their inbox.

Say it out loud

The bit after the @ that customers actually read. Everything we prove has to match it.

The From domain is what a recipient sees and, in practice, the only identity they judge. It is also the anchor for DMARC: the entire authentication apparatus exists to answer whether the proof on a message belongs to this specific domain. One message can carry three different domains, and only this one is visible.

Email headerThree domains, one messagePublished values
From: Aurora Coffee <hello@aurora.com>

The only address a human will ever see. Trust is decided here.

Return-Path: <bounce-9f3z@mail.aurora.com>

The envelope. This is the domain SPF checks, and the recipient never sees it.

DKIM-Signature: v=1; a=rsa-sha256; s=kl;
d=aurora.com; h=from:subject:date; b=hT9k...

The domain that signed the message. On a misconfigured setup this says your platform's domain instead of yours, and that is the whole bug.

Alignment — the check that fails while everything else passes — is simply the question of whether either of the bottom two domains matches the top one.

Yours

Nobody does this for you.

Where you find it

  • Klaviyo → Settings → Domains and hosting → Sending domains
  • Mailchimp → Website & Domains → Verified domains
  • Braze → Settings → Email settings → Sending domains

What goes wrong

Sending as `hello@aurora.klaviyomail.com` or a bare `noreply@`. The first fails alignment and looks like a third party; the second tells every recipient that replies are unwelcome, which is a deliverability signal as well as a rude one.

Not the same as

The display name
“Aurora Coffee” is a label anyone can type. The domain is the part that is checked.
Return-Path / envelope sender
Invisible to the recipient, and the domain SPF actually validates. They are frequently different on purpose.

The dated rule behind this

A definition is not a citation. These are the pages with the primary source, the date it was published, and what to do about it.

See also

Where this sits

Stop 2, you build the message. You choose a From address, write a subject line, and add the things the law requires to be in the message.

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.