Two verdicts, not one
- Promotions is a sort. The issue was accepted and is in the inbox area; Gmail classed it as promotional on its layout and on what readers do with mail like it. Google's help page describes the tab as deals, offers, and other promotional emails, and says Gmail learns from messages readers move between tabs.
- Spam is a judgement on the sender. Reputation, authentication, and the complaints and dead addresses the list produces. The issue is out of sight at that provider until the sender's standing changes.
The receivers' rules for bulk mail
A newsletter is bulk mail by definition, and the receivers publish what they require of it. In their words:
- Google: SPF and DKIM must both pass for the sending domain; DMARC record required for bulk senders (p=none minimum), aligned with SPF or DKIM. One-click unsubscribe (RFC 8058 List-Unsubscribe + List-Unsubscribe-Post headers) for marketing/promotional mail; honour within 2 days. Spam rate: Keep below 0.10% in Postmaster Tools; never reach 0.30%. Senders above 0.3% (since June 2024) are ineligible for Google mitigation; mitigation requires 7 consecutive days below 0.3%.
- Yahoo: SPF required; DKIM required, key ≥1024-bit (2048 recommended). One-click unsubscribe (List-Unsubscribe, preferably RFC 8058) for marketing mail; honour within 2 days; enforced from June 2024.
The full tables with dates and the checker are on Gmail and Yahoo bulk sender requirements; Microsoft's are on its own page.
What decides the spam verdict: the list and the domain
- 1
Consent you can show
Subscribers who asked, on a form that says what they will get. Google's spam-rate line is set by what recipients report, and readers report what they did not ask for.
- 2
A list that is read
Remove hard bounces on every issue and stop mailing subscribers who have not opened in months; both are the rates the receivers read. The bounce rate guide has the thresholds.
- 3
Its own domain and records
A subdomain for the newsletter, with SPF, DKIM and aligned DMARC of its own, so its reputation is separate from the company's transactional mail.
- 4
One-click unsubscribe, honoured
The RFC 8058 headers on every issue, and the request processed within two days. An unsubscribe is a complaint that did not happen.
- 5
A domain with a record
A new newsletter domain has no history at the receivers; warming builds it before the first issue and keeps it between issues.
What decides the tab: the message and the readers
Gmail sorts on the message. A newsletter laid out like a shop lands in Promotions; one written like a letter, plain text or close to it, with few links and a real reply-to, is sorted more often into Primary. The other input is the readers: every subscriber who drags an issue to Primary teaches Gmail about the sender, and Google says so. Whether the tab costs you reads is a question for your own numbers, and the Promotions page covers the decision, and the annotations for newsletters that belong in the tab.
The seed-list fix on a live issue
Seeds are how both verdicts are measured and, with MailStrike's, acted on during the send. Real, aged consumer Gmail and Outlook mailboxes on the recipient list report where the issue landed at each provider; then they open it, move it out of Promotions and spam to the primary inbox, read it with varying dwell times, and a small share mark it important. Mixed into the issue, they protect a send that starts drifting at one provider; sent the issue first, they build the signals on that content and domain before the list gets it.