Gmail, Yahoo and Microsoft sender requirements, explained
By James Bayliss · Updated · Reviewed
In this guide
Who counts as a bulk sender
All three providers use roughly the same threshold: about 5,000 or more messages in a day to their consumer mailboxes.
- Gmail counts mail to personal
@gmail.comand@googlemail.comaddresses within 24 hours, combining everything sent from the same primary domain. Once you qualify, Google treats the status as permanent. - Yahoo applies similar rules across its consumer brands, including AOL.
- Microsoft applies its rules to Outlook.com, Hotmail.com and Live.com consumer addresses.
Mail to business mailboxes (Google Workspace, Microsoft 365 tenants) doesn't count towards the thresholds. Those organisations apply their own filtering, which often follows the same signals.
The requirements side by side
| Requirement | Gmail (all senders) | Gmail / Yahoo bulk | Outlook.com bulk |
|---|---|---|---|
| SPF or DKIM | Required | Both required | Both required |
| DMARC record | Recommended | Required, minimum p=none | Required, minimum p=none |
| DMARC alignment (SPF or DKIM) | — | Required | Required |
| Valid forward and reverse DNS (PTR) | Required | Required | Expected |
| TLS for transmission | Required | Required | Expected |
| One-click unsubscribe (RFC 8058) | — | Required for marketing mail | Unsubscribe link required |
| Spam-complaint rate | Below 0.3% | Below 0.3%, aim for 0.1% | Keep low |
The table summarises the providers' published guidance; check the sources at the end before relying on a detail, as providers update their pages.
The requirements in detail
Authentication
Bulk senders must pass both SPF and DKIM, not just one. DKIM keys should be at least 1024 bits, and 2048-bit keys are recommended. See SPF explained and DKIM selectors.
DMARC and alignment
Publish a DMARC record at _dmarc.<your-domain>. Gmail explicitly accepts p=none, but the record must include a policy tag: a record with no p= produces error 4.7.31. The From: domain must align with the domain that passed SPF or DKIM. Forwarded and mailing-list mail is exempt from the alignment requirement. See DMARC alignment, explained.
Reverse DNS
Every sending IP needs a PTR record whose hostname resolves back to the same IP (forward-confirmed reverse DNS). Gmail returns temporary error 4.7.23 or permanent error 5.7.25 when this fails. The reverse DNS guide explains how to set it with your ISP or cloud provider.
One-click unsubscribe
Marketing and promotional messages need these headers (RFC 8058):
List-Unsubscribe: <https://example.com/unsub?u=abc123>
List-Unsubscribe-Post: List-Unsubscribe=One-Click
A mailto: link or a link only in the message body doesn't satisfy the requirement. Honour requests within two days. Transactional mail, such as receipts and password resets, is exempt.
Spam-complaint rate
Gmail measures the share of your messages that recipients mark as spam, shown daily in Postmaster Tools. Stay below 0.3%, and aim for under 0.1%. A sender at or above 0.3% loses eligibility for mitigation help until the rate stays below it for seven consecutive days.
What happens if you don't comply
- Gmail began enforcing in February 2024 with temporary deferrals and spam-folder placement. It started ramping up to temporary and permanent rejections in November 2025, with faster timelines for newer sending domains.
- Yahoo followed the same February 2024 timeline.
- Microsoft started enforcing for Outlook.com consumer domains on 5 May 2025. Non-compliant bulk mail can be rejected with
550 5.7.515 Access denied, sending domain [domain] does not meet the required authentication level.
A compliance checklist
- SPF record present, valid and under 10 lookups (Email Record Lookup)
- DKIM signing on every sending platform, with your domain in
d= - DMARC record with
p=andrua= - Every stream aligned: check
Authentication-Resultson a test message - PTR set and forward-confirmed for each sending IP (Email Blacklist Check checks this too)
- One-click unsubscribe headers on marketing mail
- Postmaster Tools (Google) and SNDS (Microsoft) set up to watch complaint rates and IP reputation
From the field: One of the biggest annoyance items I have run into was sending through SendGrid and getting misalignment errors. The problem turned out to be a strict alignment flag in the DMARC record was failing the SendGrid alias because it did not exactly match our sending domain.So be careful with what flags you set in your DMARC when working with bulk senders.
Sources
Check it now
Email Record Lookup Is this domain's email set up correctly: MX, DMARC, DKIM and SPF?
Related guides
- Why is my email going to spam? A diagnostic checklist for admins
A step-by-step checklist for why legitimate mail lands in junk: authentication, alignment, IP and domain reputation, reverse DNS, content and list hygiene.
- DMARC from p=none to p=reject without breaking mail
How to move DMARC from monitoring to enforcement: what to publish, which reports to read, how long each stage takes, and what to do with what they find.
- Reverse DNS (PTR) for mail servers: setup and FCrDNS
Why receivers require a PTR record on sending IPs, what forward-confirmed reverse DNS means, who can set the record, and how to fix 4.7.23 and 5.7.25 bounces.