Transactional email

The mail that must arrive: what qualifies, and why it needs its own lane.

Transactional email is mail triggered by a recipient's own action or account state: receipts, password resets, shipping notices, security alerts. Marketing email is the opposite case, sent at the sender's initiative to many people at once to promote something.

Why it matters

The two carry different expectations, different law, and different risk. A password reset must arrive in seconds, every time, including to people who have unsubscribed from everything else. Legally, consent rules target commercial mail: transactional messages can generally be sent without marketing consent and are exempt from unsubscribe requirements, an exemption you forfeit the moment you stuff promotions into a receipt. Operationally, if both kinds of mail share one sending reputation, a bad newsletter day can push your password resets into the spam folder, which is the most expensive place a reset can go.

In practice

The answer is separation into streams: distinct message categories riding distinct subdomains and IPs, with separately scoped suppression. A worked example: a user unsubscribes from your newsletter. Their address is suppressed for the marketing stream, and when they forget their password next month, the reset still arrives, because the transactional scope was never touched. The discipline cuts the other way too: keep marketing content out of the transactional stream, both to preserve its legal status and to keep its reputation pristine.

How Email Fast handles it

Every Email Fast message declares a stream, and transactional and marketing streams ride separate reputations end to end. A newsletter unsubscribe can never block a password reset; the scoping is structural, enforced at the same admission gate as everything else, not a checkbox someone can miss. One-click unsubscribe headers go on marketing mail, where they belong.