Email deliverability: why newsletters land in spam and how to fix it

The technical foundation: SPF, DKIM and DMARC

These three DNS records prove to mailbox providers that a message really comes from you. SPF lists the servers allowed to send on your behalf. DKIM cryptographically signs each message. DMARC ties both together and tells providers what to do with mail that fails the checks.

Good email platforms walk you through setup and show whether the records are correct. Never send from a free address like Gmail; always use your own domain.

What Gmail and Yahoo require from bulk senders

Senders who mail these providers at volume must, among other things, have:

• SPF and DKIM authentication plus a DMARC record
• One-click unsubscribe in the message header
• A spam complaint rate well below 0.3 percent

List hygiene: fewer recipients, better results

Purchased lists and long-inactive contacts hurt your reputation. Use confirmed opt-in where practical, and either remove contacts who haven't engaged for months or target them with a re-engagement campaign first.

Hard bounces — addresses that don't exist — should be suppressed immediately. Most platforms do this automatically; confirm it's enabled on your account.

Content and sending cadence

Mailbox providers watch how recipients respond. Opens, replies and moving mail into folders are positive signals; deleting unread or marking as spam are negative. A steady cadence and content that matches what people signed up for matter more than any wording trick.

What to look for in a platform

Most vendors send from shared IPs; at high volume a dedicated IP can make sense, but it has to be warmed up gradually. For most teams, clear domain authentication guidance, bounce and complaint reporting, and separating marketing from transactional email matter more.