Email Authentication Sender Requirements 2025
Major mailbox providers Google, Yahoo, and Microsoft have raised the bar on email authentication to improve inbox security and reduce spam. If you send email in bulk (especially over 5000 messages a day), these changes likely affect you.
Senders Sending < 5k Emails/Day
| Requirement | Status |
|---|---|
| SPF / DKIM | SPF or DKIM must PASS |
| DMARC | Optional |
| Alignment | When DMARC enforced |
Senders Sending ≥ 5k Emails/Day
| Requirement | Status |
|---|---|
| SPF / DKIM | SPF and DKIM must PASS |
| DMARC | at least p=none |
| Alignment | SPF or DKIM must align |
Rollout Timeline
- Google: Enforced since February 2024
- Yahoo: Enforced since February 2024
- Microsoft: Enforcement begins May 2025
Why This Matters
Without proper authentication:
- Your emails might be flagged or rejected.
- Your brand reputation and deliverability can suffer.
- You risk non-compliance with provider policies.
If you send more than 5000 emails per day, make sure:
- SPF and DKIM both pass.
- DMARC is published with at least
p=none. - Alignment checks are met for either SPF or DKIM.
Bottom line: Whether you're a marketer, developer, or sysadmin, aligning with these new requirements is essential for reaching inboxes reliably.