Transactional email

One person did one thing, and this mail is the consequence: a receipt, a password reset, a shipping notice, a magic link or a one-time code. That origin is the whole definition, and it decides everything else about the design. Marketing mail is sent to a list on a schedule somebody chose; a transactional mail is sent to one address at a moment that address caused, which is why it is expected, why it is opened at rates no campaign will ever reach, and why it needs no consent and no way out of a list nobody joined.

The design brief is short. Put the one fact at the top, because a mail client shows about three lines before a reader decides whether to open it and the answer to “did it work” belongs in those lines rather than under a banner. Then write for a reader who is not in front of the product: this is the document somebody searches their mailbox for eleven months later, when the order number and the amount are the only things they need, so the copy is a record and its most important quality is that it is still legible out of context. Everything ornamental competes with that.

The failure mode is smuggling. Because these mails are opened, they are the most valuable real estate a company has, and the temptation is to put a campaign in the receipt. It costs twice. It displaces the record, so the fact somebody opened the mail for is now below a promotion. And it changes what the mail legally is, since a message carrying marketing generally needs the consent and the unsubscribe link a genuine receipt does not, which is exactly the consent nobody collected when they took a card number. A cross-sell in a receipt is not a free impression, it is a marketing mail with the deliverability privileges of a receipt.

Two practical notes follow from the same place. Send transactional mail on a different sending identity from campaigns, so a marketing complaint cannot take password resets down with it. And keep the two kinds of mail honest about which they are, rather than letting a “your order shipped” template slowly acquire a newsletter: the distinction is the reason this mail is trusted, and it is spent the first time it is abused.