Gmail, Yahoo and Outlook Bulk Sender Requirements
· 4 min read
In February 2024, Gmail and Yahoo started enforcing new rules for anyone sending large volumes of email to their users. In May 2025, Microsoft followed with similar rules for Outlook.com, Hotmail and Live addresses. If you send newsletters, product updates or other mail to many people, these rules decide whether your messages reach the inbox.
This guide summarises what each provider asks for, as published by the providers. Rules change, so check the providers' own sender guidelines before making big changes. Facts here are current as of October 2026.
Who counts as a bulk sender?
- Gmail defines a bulk sender as one that sends close to 5,000 or more messages to personal Gmail accounts within 24 hours. Messages from all subdomains of the same domain are counted together. Google says that once a domain reaches this level, it is treated as a bulk sender from then on.
- Yahoo applies its requirements to bulk senders without publishing an exact number, and asks every sender to authenticate.
- Outlook.com (Microsoft's consumer mail, including Hotmail and Live) applies its rules to domains sending more than 5,000 messages a day to its users.
Even if you are below these numbers, following the same rules helps your delivery everywhere.
Gmail and Yahoo: the 2024 requirements
Gmail and Yahoo coordinated their announcements in late 2023 and began enforcing in February 2024. The core requirements for bulk senders are:
- Authenticate with SPF and DKIM. Both records must be in place for the sending domain. (All senders, not only bulk senders, need at least one of them.)
- Publish a DMARC record. A policy of
p=noneis enough to meet the requirement. - Align the From domain. The domain in the visible From address must match the domain that passes SPF or DKIM.
- Offer one-click unsubscribe. Marketing and subscribed messages must support one-click unsubscribe using the
List-UnsubscribeandList-Unsubscribe-Postheaders defined in RFC 8058, and include a visible unsubscribe link in the message. Unsubscribe requests must be honoured within two days. Gmail gave senders until 1 June 2024 to add this. - Keep spam complaints low. The spam rate reported in Google Postmaster Tools should stay below 0.3 percent. Google recommends staying below 0.1 percent.
- Meet basic technical standards. Send over a TLS connection, use sending IPs with valid forward and reverse DNS, and format messages according to RFC 5322.
Google has said it enforces these rules gradually: first with temporary errors on part of non-compliant traffic, then with more rejections over time. Starting in November 2025, it began rejecting a growing share of non-compliant mail.
Outlook.com: the 2025 requirements
Microsoft announced its rules in April 2025 and started enforcing them on 5 May 2025. For domains sending more than 5,000 messages a day to Outlook.com, Hotmail and Live addresses, it requires:
- SPF that passes for the sending domain.
- DKIM that passes, so the message is signed and unchanged.
- DMARC with at least
p=none, aligned with SPF or DKIM.
Microsoft said mail that does not meet these rules would first be sent to the Junk folder, and later rejected outright. It also recommends, without making them hard requirements, a working unsubscribe link, valid From and Reply-To addresses, and regular removal of invalid addresses.
A checklist you can work through
| Requirement | Gmail | Yahoo | Outlook.com |
|---|---|---|---|
| SPF and DKIM | Required | Required | Required |
| DMARC (at least p=none) | Required | Required | Required |
| From domain aligned | Required | Required | Required |
| One-click unsubscribe (RFC 8058) | Required | Required | Recommended |
| Low spam complaint rate | Under 0.3% | Under 0.3% | Recommended |
If DNS records are new to you, start with SPF, DKIM and DMARC explained. It includes example records and a safe order to roll them out.
Where list quality comes in
Authentication proves who you are, but providers also watch how people react to your mail. Sending to addresses that do not exist, to abandoned inboxes, or to people who never asked for your email all push in the wrong direction. Hard bounces hurt your reputation, and recipients who do not remember signing up are the ones most likely to press "report spam".
- Only email people who opted in. This is the best way to keep complaint rates low.
- Check addresses at signup so typos and fake addresses never reach your list. See how to validate email addresses at signup.
- Verify older lists before sending. Use bulk email verification to remove invalid and disposable addresses.
- Remove bounces and long-term inactive subscribers. Read how to reduce your email bounce rate for the full list.
Want to check a single address quickly? Try the free email checker. It tests the format, typos and the domain's mail servers in a second, without an account.