[ Guide ]

Deliverability.
The part nobody
sees.

The best email in the world earns nothing in a spam folder. Mailbox providers decide where your mail lands based on who you are, whether you can prove it and how people react to what you send. Here’s what they now require, and what we do to keep Shopify brands in the inbox.

The rules for bulk senders

Since February 2024, Gmail and Yahoo have required brands sending in volume to meet a baseline. Microsoft introduced similar requirements for Outlook.com addresses in 2025. In practice, every growing Shopify brand should meet all of them:

• Authentication. SPF and DKIM set up for your sending domain.
• DMARC. A published DMARC record, with your From address aligned to the domain that’s authenticated.
• One-click unsubscribe. Marketing email must offer a one-click unsubscribe in the message headers as well as a visible link, and unsubscribes must be honoured within two days.
• Low complaint rates. Google asks senders to keep the spam rate shown in Postmaster Tools below 0.3%, and ideally well under 0.1%.

Use your own sending domain

By default, Klaviyo can send on your behalf from a shared domain. A branded sending domain, set up with a few DNS records, means your reputation is your own: it’s built by your sending and isn’t affected by anyone else’s. It also lets your From address align properly for DMARC. If you haven’t set one up, it’s usually the first fix.

Send to people who want it

Mailbox providers watch engagement. Repeatedly mailing people who never open tells them your mail isn’t wanted. Three habits make the biggest difference:

• Segment campaigns by engagement. Send most campaigns to people who’ve opened, clicked or bought recently, and mail the wider list only occasionally.
• Run a sunset flow. Give unengaged profiles a last chance, then suppress them.
• Collect consent cleanly. Clear sign-up forms, no bought lists, and double opt-in where list quality is a problem.

Watch the signals

• Google Postmaster Tools for spam rate and domain reputation at Gmail.
• Bounce, unsubscribe and spam complaint rates for each campaign in Klaviyo.
• Sudden drops in open or click rates at one mailbox provider, which often show a placement problem before revenue does.

Signs something is wrong

• Revenue from campaigns falling while list size grows.
• Customers saying your emails went to spam or promotions and they missed a launch.
• Spam complaints rising after you mail older segments.

Deliverability is included in every Ember engagement, and it’s one of the five areas the free audit covers.