Meet the bulk sender rules

Meet the sender rules of Gmail, Yahoo and Microsoft before you send more than 5,000 messages a day to any of them.

By Erik Bergstedt, Agent Wranglers. Updated 20 October 2026.

How to do it

Gmail and Yahoo have enforced these rules since February 2024, and Microsoft's Outlook.com since May 2025. Mail that fails them is delayed or rejected. Set up SPF and DKIM, and DMARC with at least p=none. Align the From domain with SPF or DKIM. Give every sending IP matching forward and reverse DNS. Send over TLS. Format messages as RFC 5322 sets out. Add one-click unsubscribe and a visible unsubscribe link to marketing mail, and honour it within two days. Keep the spam complaint rate below 0.1%, and never let it reach 0.3%. Small senders still need SPF or DKIM, and benefit from all of it.

Example

SPF:   PASS with IP 192.0.2.10
DKIM:  'PASS' with domain news.example.com
DMARC: 'PASS'

How to check

Send a test message to a Gmail address and open "Show original". SPF, DKIM and DMARC all say PASS, and the message arrived over TLS. Google Postmaster Tools shows every compliance item for the domain as met.

For agents: if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in Based on the Agent Wranglers email playbook: https://agentwranglers.se/playbook/email/deliverability/bulk-sender-rules.