What is a safe sending frequency?

Whatever the audience signed up for and engages with. Weekly is common for newsletters; more than that needs a very engaged list. The signal is complaints and unsubscribes per send rising — that is the list telling you it is too much.

Should we use a dedicated IP?

Only at high volume with a team to manage its reputation. Below that, a good shared pool from a reputable provider performs better because its reputation is maintained for you. Domain reputation matters more than IP for most senders now.

How do we re-engage a dormant list safely?

In small batches, oldest last, with a message that asks whether they still want to hear from you and removes those who do not respond. Sending a big campaign to a list that has not been mailed in a year is the fastest way to trigger filtering.

← Blog·Lifecycle & messaging

Email deliverability for marketing senders: getting into the inbox and staying there

Authentication, list quality, engagement-based sending, sunset policies and the monitoring that catches a reputation slide before it becomes a spam-folder problem.

07 Jan 2026 · 2 min read · by HeiSyn

Marketing email has a deliverability problem that arrives slowly: open rates drift down, then a mailbox provider starts filtering, then a whole domain lands in spam and nobody can say when it started. The causes are always the same — sending to people who do not engage, from a domain that is not properly authenticated, at a frequency the audience did not choose. Prevention is a set of policies, not a tool.

Authentication and identity

SPF, DKIM and DMARC with an enforcing policy on the sending domain, aligned with the from address. A dedicated subdomain for marketing so its reputation is separate from your transactional and corporate mail. BIMI once DMARC is enforced, for the logo in the inbox. List-unsubscribe headers with one-click unsubscribe, which the major providers now require for bulk senders.

List quality

Double opt-in, or at least a confirmation for addresses collected offline. Validation of new addresses before the first send. Immediate removal of hard bounces and complaints. Never a purchased list, ever, on the same domain as anything you care about.

Engagement-based sending

Send more to people who open and click, less to people who do not, and stop sending to people who have not engaged in six months except for a single re-permission message. This is the single biggest lever: mailbox providers rate you on how recipients behave, and unengaged recipients drag the rating down for everyone.

Monitor and react

Open and click by mailbox provider, bounce and complaint rates per send, spam-folder placement tested on seed accounts, and Google Postmaster and Microsoft SNDS data weekly. A complaint rate creeping toward a tenth of a percent is the alarm; throttle, clean and warm back up before it becomes a block.

Questions people ask next

What is a safe sending frequency?: Whatever the audience signed up for and engages with. Weekly is common for newsletters; more than that needs a very engaged list. The signal is complaints and unsubscribes per send rising — that is the list telling you it is too much.
Should we use a dedicated IP?: Only at high volume with a team to manage its reputation. Below that, a good shared pool from a reputable provider performs better because its reputation is maintained for you. Domain reputation matters more than IP for most senders now.
How do we re-engage a dormant list safely?: In small batches, oldest last, with a message that asks whether they still want to hear from you and removes those who do not respond. Sending a big campaign to a list that has not been mailed in a year is the fastest way to trigger filtering.

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