Quick answer: If you send more than 5,000 messages a day to Gmail, you must authenticate with SPF, DKIM and DMARC, offer one-click unsubscribe and honour it within two days, and keep spam complaints under 0.3%. Yahoo and Microsoft follow the same playbook. Fail these and your mail is rejected, not just filtered.
What changed, and when
- February 2024 — Gmail and Yahoo require senders of 5,000+ messages a day to authenticate with SPF, DKIM and DMARC, keep spam complaints low and make unsubscribing easy. Google stops offering delivery mitigation to senders who do not comply.
- 1 June 2024 — Gmail’s deadline for one-click unsubscribe in all commercial and promotional mail.
- June 2024 — bulk senders with a user-reported spam rate above 0.3% become ineligible for Gmail mitigation.
- May 2025 — Outlook.com, Hotmail and Live.com apply similar rules to domains sending 5,000+ emails a day: SPF, DKIM and at least a
p=noneDMARC record, announced by Microsoft in April 2025. - November 2025 — Gmail ramps up enforcement: non-compliant mail now faces temporary and permanent rejections, not just spam-foldering.
Gmail milestones from Google’s email sender guidelines FAQ; Outlook from Microsoft’s announcement. Last reviewed 27 October 2026.
In October 2023 Google announced new rules for bulk senders, and they took effect from February 2024. Yahoo announced the same. This page is the tick-list. For the wider picture, read the complete guide to email deliverability.
No matter who their email provider is, all users deserve the safest, most secure experience possible. In the interconnected world of email, that takes all of us working together.
— Marcel Becker, Sr. Director of Product, Yahoo
Who counts as a bulk sender?
More than 5,000 messages to Gmail addresses in a day.
Google defines a bulk sender as anyone sending more than 5,000 messages to Gmail addresses in one day (Google, 2023). Cross that once and you’re expected to meet the rules. Honestly, every sender should meet them anyway — Google itself calls them “basic email hygiene.”
The three requirements
Authenticate, let people leave, don’t annoy people.
- 1. Authenticate — SPF, DKIM and DMARC on your sending domain (Google, 2023)
- 2. One click — one-click unsubscribe, actioned within 2 days (Google, 2023)
- 3. Under 0.3% — spam-complaint rate (aim under 0.1%) (Gmail sender guidelines)
The first one is the big one, and it is the one people fail. Our step-by-step SPF, DKIM & DMARC setup guide walks through exactly what to paste.
Watch out: These are reject rules, not spam-folder rules. Mail that fails authentication is bounced back. Your campaign simply does not arrive.
The checklist
Work down this list before your next send.
2026 sender-requirements checklist
- SPF record published (one only, merged if you had one)
- DKIM signing enabled and the record published
- DMARC record published at _dmarc (start at p=none)
- A test to Gmail shows SPF + DKIM + DMARC = PASS
- One-click unsubscribe header enabled on every campaign
- Unsubscribes actioned within 2 days (your tool should be instant)
- Spam complaints under 0.3% — check your reports
- Sending from your own authenticated domain, not a free address
- Unengaged contacts suppressed so complaints stay low
Tip: Complaints creeping up? The fix is almost always list hygiene, not copy. See the list-cleaning section of the deliverability guide.
Common questions
What happens if I don’t comply?
Your mail gets rejected rather than delivered. Google began enforcing from February 2024, and unauthenticated bulk mail is bounced.
I send fewer than 5,000 a day — do these apply to me?
The bulk-sender rules technically kick in above 5,000 a day to Gmail, but Google describes these practices as basic hygiene. Do them anyway; they’re the difference between the inbox and the spam folder.
What is one-click unsubscribe?
A standard header that puts a real unsubscribe link at the top of the message, so a reader can leave in one click. You must process those requests within two days.
How do I check my spam-complaint rate?
Google Postmaster Tools shows it for Gmail. Keep it under 0.3%, and ideally under 0.1%.
Does Microsoft have the same rules?
Microsoft has moved in the same direction, requiring authentication for high-volume senders. Meeting the Google and Yahoo requirements puts you in good shape across the board.
How Bluey handles each requirement
The 2024 bulk-sender rules are a checklist, and roughly half of it is the platform’s job. Here is the split, so you know what is left for you.
- SPF, DKIM and DMARC — yours to publish, ours to generate and verify. Use the record generator, then check it in Settings → Sending domains.
- One-click unsubscribe — handled. The required
List-UnsubscribeandList-Unsubscribe-Postheaders are added to every marketing send automatically. - Unsubscribe honoured within two days — handled. Suppression is immediate and account-wide.
- Complaint rate under 0.3% — monitored and surfaced, but driven by what you send and who you send it to. This is the one you own.
- Valid forward and reverse DNS, TLS — handled by the sending infrastructure.
- Do not mix streams — marketing and transactional are metered and reputation-tracked separately, so a campaign cannot damage delivery of your receipts.
Related guides
- How to set up SPF, DKIM & DMARC (How-to)
- The complete guide to email deliverability (Deliverability)
- How to start email marketing (Start here)
- Generate your SPF, DKIM & DMARC records (Free tool)
- Suppression & compliance (Product)
Sources: Bulk-sender definition (5,000+/day), the three requirements, and the Marcel Becker quote — Google/Gmail blog (Oct 2023). Spam-complaint threshold and enforcement details — Gmail sender guidelines.