How to check your domain against Gmail's sender rules

Gmail publishes rules for people who send email to Gmail addresses. Some apply to every sender and some apply only to bulk senders. This guide is a self-check you can run on your own domain: what to look at, in what order, and what to fix first. It does not replace Google's own page, which we link below.

For the rules from each provider side by side, see Gmail and Yahoo sender requirements.

Step 1: list everything that sends as your domain

Your mailbox provider is only one of them. A website contact form, an invoicing tool, a CRM, a newsletter service and a booking system often send mail that shows your domain in the From line. Write each one down. Every item on the list needs its own authentication, and a forgotten tool is the usual reason a domain passes in one place and fails in another.

Step 2: check what applies to every sender

Google's sender guidelines say all senders to Gmail need to set up SPF or DKIM for the sending domain, use valid forward and reverse DNS records for sending servers, and send over a TLS connection. Google also says to keep the spam rate reported in Postmaster Tools below 0.3%. If you use a mainstream mailbox provider, DNS records and TLS are normally handled for you, so the part to confirm is that SPF or DKIM is switched on for the domain and for each tool from step 1.

Google recommends a DKIM key of 2048 bits where your provider supports it, and asks for at least 1024 bits.

Step 3: find out whether you count as a bulk sender

Google defines bulk senders as those sending more than 5,000 messages a day to Gmail addresses. If you send a newsletter or a sales sequence, add up the messages that go to Gmail addresses in one day across all your tools. Most small businesses sending one-to-one mail are well under that line, and a newsletter list may or may not reach it. If you are over, or close, treat the next step as required instead of optional.

Step 4: add the bulk sender items, or add them anyway

For bulk senders, Google asks for SPF and DKIM together with a DMARC record, which can be set to a policy of none. The domain in your From line has to line up with the SPF domain or the DKIM domain for each message. Marketing and subscribed messages need one-click unsubscribe and a clearly visible unsubscribe link in the body. Even if you are below the line, a DMARC record with a report address costs little and gives you data on who is sending as your domain.

Step 5: send yourself a test and read the result

Send a message from each tool on your list to a personal Gmail address you control, open it and view the message source or the original headers. Look for the SPF, DKIM and DMARC results and check that each says pass for the domain you expect. A tool that fails is the one to fix first. Our plain-English guide to SPF, DKIM and DMARC explains how to read those results.

Step 6: watch the spam rate

Postmaster Tools shows the spam rate for mail sent to personal Gmail accounts, along with authentication results and delivery errors. Google says to keep the rate below 0.10% and to avoid reaching 0.30%. A small sender may see little or no data if few messages go to Gmail each day, and an empty dashboard does not mean you are failing.

What to do when something fails

Fix authentication first, because it is the part you control directly. Then look at the list: send only to people who expect your mail, remove addresses that bounce and honor unsubscribe requests quickly. Meeting the published rules removes a common reason for filtering or rejection, and it does not promise inbox placement. Providers still judge each message.

Where to go from here

For the full rules from Gmail, Yahoo and Outlook side by side, read Gmail and Yahoo sender requirements for small businesses, which also has a form for sending us your domain for a check. For fixes after a failed test, see the email deliverability fix. Passieon is an independent agency with no connection to Google, Yahoo or Microsoft, and the rules change, so read the current version.

Sources

• Google Workspace Admin Help: Email sender guidelines, read November 10, 2026.
• Passieon: Gmail and Yahoo sender requirements for small businesses, read November 10, 2026.