When an agency sets up a rebranded email course or nurture sequence for a client, the emails usually go out under the client’s name and domain. Whether they land in the inbox depends partly on technical records that only the domain owner can publish. This checklist covers what Gmail and Yahoo ask of senders as of October 2026 and how to organize that work when the domain belongs to someone else. For a general overview of the rules for product sellers, see our sister site’s guide to Gmail’s sender rules.
What the Mailbox Providers Ask For
Google’s Email sender guidelines and Yahoo’s Sender Best Practices set similar baselines:
- All senders: authenticate mail with SPF or DKIM, have valid forward and reverse DNS for sending servers, and keep the spam rate reported in Google Postmaster Tools below 0.3%.
- Bulk senders (Google defines these as sending more than 5,000 messages a day to Gmail addresses): use both SPF and DKIM, publish a DMARC record (a policy of “none” is accepted), and make sure the From: domain aligns with the SPF or DKIM domain.
- Unsubscribing: marketing messages from bulk senders need one-click unsubscribe headers plus a visible unsubscribe link in the body. Yahoo asks senders to honor unsubscribes within two days.
Google also states that if you provide sending services to clients, you are responsible for their sending practices. For an agency that runs campaigns on a client’s behalf, that makes list quality and consent part of the job, not an afterthought.
A Setup Checklist for Client Domains
- Confirm who controls DNS. SPF, DKIM and DMARC are DNS records on the client’s domain. Ideally the domain and DNS account are in the client’s name, with the agency given delegated access.
- List every service that sends mail. Google advises that a domain’s SPF record should include all of its senders. A client may already use a workspace mail provider, a help desk and an invoicing tool alongside the new email platform.
- Authenticate the email platform. Follow the platform’s own domain-authentication steps so it signs messages with DKIM for the client’s domain, then publish the records it provides.
- Add or review DMARC. If the client has no DMARC record, start with a monitoring policy and a reporting address so problems show up before stricter settings are considered.
- Send tests to personal Gmail and Yahoo inboxes. Check the message headers for passing SPF, DKIM and DMARC results before the first real send.
- Document everything in the handoff. Record which records were added, where, and why, so the client’s next provider does not delete them by mistake.
Keep the List Clean
Authentication proves who sent a message; it does not make unwanted mail welcome. Import only contacts who opted in, remove addresses that bounce, and watch complaint rates after each send. Mailbox providers can still filter well-authenticated mail if recipients mark it as spam.
More White-Label Guides
- Client Domain Names and Accounts: Keeping Ownership Clear From Day One
- Rebranding a Done-for-You Funnel for a Client: Pages, Emails and Sender Details
- Inside a Done-for-You Email Course: What to Look For