Google and Yahoo sender requirements: a checklist for Shopify merchants

Gmail and Yahoo Mail check every store’s email against a short list of rules. Most of the work happens in your email tool, and a few numbers decide how much of it applies to you. This page lists those rules in the order a merchant meets them, with the numbers each provider gives. It was checked against the providers’ own pages on October 24, 2026, and the rules change, so re-read both pages before a big change to your sending.

Who counts as a bulk sender

Google’s help page says: “A bulk sender is any email sender that sends close to 5,000 messages or more to personal Gmail accounts” in a 24-hour period. Google adds that “Senders who meet the above criteria at least once are permanently considered bulk senders.”

So one big sale campaign can put a store in the bulk group for good. Here is how that happens: A store with 6,000 subscribers on personal Gmail addresses sends one sale campaign to all of them. That is 6,000 messages to Gmail in one day. Worked example (made up)

Yahoo’s Sender Hub lists “Requirements for Bulk Senders” and gives no message count that makes a sender a bulk sender. If you are unsure which group you are in, treat the stricter list as yours.

What every sender must set up

Google’s sender guidelines ask all senders for two things:

• Authentication: “Set up SPF or DKIM email authentication for your sending domains.”
• Spam rate: “Keep spam rates reported in Postmaster Tools below 0.3%.”

Google also asks that the sending IP address match its PTR record and that email travels over TLS. Those belong to the email tool that sends for you, so ask it how it handles them. This page does not say what Klaviyo, Shopify Email, Mailchimp or any other tool sets up for you, because the providers’ pages do not say it either.

The unsubscribe rules

Google says one-click unsubscribe “is required only for marketing and promotional messages”, and transactional messages are excluded. It works through List-Unsubscribe headers (RFC 8058), which remove the person from the list directly.

Yahoo asks bulk senders to “Honor unsubscribes within 2 days”. Google’s page recommends that senders “fulfill unsubscribe requests within 48 hours”. Plan for two days. Your email tool normally processes unsubscribes for you, and it is worth checking how fast it does.

The spam-rate thresholds

Google gives a target and a ceiling. Senders should keep their spam rate below 0.1% and “should prevent spam rates from ever reaching 0.3% or higher.” A bulk sender above 0.3% loses eligibility for mitigation until its rate stays “below 0.3% for 7 consecutive days.” Yahoo asks bulk senders to keep the rate below 0.3%.

Google describes the figure as the user-reported spam rate, so every reader who reports an email counts against you. A person who receives the same newsletter twice is one such reader. We found no study that ties duplicate customers to complaint rates. The link is our reasoning: a duplicate address gives the same person a second email and a second chance to complain.

List hygiene

Yahoo’s advice is direct: “Remove invalid recipients from your list promptly.” The page also suggests watching hard and soft bounces and inactive recipients, and sending a reconfirmation email to people who have stopped opening.

Two jobs in your Shopify list fall under this. Mistyped addresses never receive anything, so fix them with contact fixes or correct them by hand. Duplicate subscribed addresses double your sends; the same newsletter twice shows how to find them and leave the extra address out without changing anyone’s consent. See list hygiene for the wider habit.

Last checked

Google’s pages show no update date, only the 2026 footer. Yahoo’s page says “Beginning in February 2024, enforcement of the following sending standards will take effect.” Last checked: October 24, 2026. This is guidance about email deliverability, and your email tool’s own documentation is the place to confirm what it handles for you.