How this works
Methodology
A reference is only worth citing if you can see how it was made. This page is the contract.
What counts as a source
A rule ships only with a primary source that was read: the regulator’s own publication, the court’s own opinion, the mailbox provider’s own documentation, the RFC, or the platform’s own help centre. Law-firm summaries and trade press are useful for finding things and are never the citation. If a claim cannot be dated, it does not go in.
Why every page states enforcement honestly
An obligation existing and an obligation being enforced are different facts, and conflating them is how compliance content becomes fear-selling. Where nobody has been fined, the page says nobody has been fined. That costs us urgency and buys the thing worth more, which is being trusted the one time it really matters.
Re-verification
Every rule carries a last-verified date. Pages older than 90 days show a warning saying so rather than quietly pretending to be current. The last full review of the corpus was 1 Aug 2026.
Corrections
Send them to corrections@emailrules.today. Corrections are published in the page history with a date and a credit to whoever caught it. If we got something wrong, the record of being wrong stays visible.
Conflicts of interest
We sell no tracking pixels, no seed-list testing, no inbox-placement scores and no ESP. We do sell continuous monitoring against these rules, which is disclosed on every page that mentions it. That is the only commercial relationship this site has, and it is why it can tell you when a tracking pixel is a liability.
Not legal advice
This is a reference for practitioners, written by practitioners. It is not legal advice and no lawyer reviewed it. Confirm anything load-bearing with your own counsel before you rely on it.