What do Google and Yahoo actually require from cold email senders?

Google and Yahoo ask bulk senders to authenticate with SPF and DKIM, publish a DMARC policy, support one click unsubscribe and keep the spam rate under 0.30%. Google also tells senders to aim for 0.10%. Yahoo asks for unsubscribes to be honored within 2 days. Cold senders who stay far below bulk volume still gain from the same setup.

This post lists what the two providers say on their own pages, in their words where the number matters. We read both pages on 19 October 2026. Sellinger is not a deliverability tool, and this is not a promise that following the list lands you in the inbox. It is the minimum that mailbox providers say they look at.

Who counts as a bulk sender?

Google's Email sender guidelines set the extra rules for bulk senders, meaning senders of 5,000 or more messages a day, and say they took effect on 1 February 2024. The Yahoo Sender Hub page we read lists requirements for bulk senders but does not state a volume that triggers them.

Most cold email programs send far less than 5,000 a day. That does not make the rules irrelevant. A mailbox provider has no way to know in advance that you are small. It sees authentication results, complaint rates and what recipients do with your mail. A cold sender who is missing SPF or DKIM looks like a risky sender at any volume.

What do Google and Yahoo require, one item at a time?

If your mail is sent through a mailbox provider such as Google Workspace or Microsoft 365, the transport and DNS lines are handled by the provider. The lines that stay with you are the ones about your own domain: SPF, DKIM, DMARC, the unsubscribe mechanism and your complaint rate.

What is the difference between 0.10% and 0.30%?

Google gives two numbers for the same measure. The requirement is to keep the spam rate in Postmaster Tools below 0.30%. The sending practices advice is to keep it below 0.10% and never reach 0.30%. Read the first as the line you must not cross, and the second as the level to run at.

In plain numbers: 0.10% is one complaint for every 1,000 messages delivered to the inbox, and 0.30% is three for every 1,000. A cold campaign to 1,000 people that draws three spam complaints is already at the limit. Cold mail is more exposed to this than a newsletter, because the recipients did not ask for it. That is the reason the list and the message matter as much as the DNS records.

Does one click unsubscribe apply to cold email?

Both providers word the rule for "marketing and subscribed messages". Cold outreach written as one person to one person is not clearly a marketing message in the way a newsletter is, and neither page says how it treats it. The safe reading is practical: if your message sells something to people who did not sign up, assume the rule can be applied to it.

The mechanism is two headers. Google's page gives them as List-Unsubscribe-Post: List-Unsubscribe=One-Click and List-Unsubscribe: <URL>. When a recipient clicks unsubscribe in the mail client, the client sends a POST request to your URL. Google adds that other unsubscribe options may supplement one click, but should not replace it. Yahoo says the mailto method is acceptable and the POST method is highly recommended.

Sellinger supports this. Cold email can carry an unsubscribe line and the standard one click headers (List-Unsubscribe and List-Unsubscribe-Post). It is a setting on each mailbox, and it is off by default. If you send cold email from a mailbox, switch it on. See what Sellinger enforces for the full list of rules in the product.

What should you check before the first campaign?

Use this as a pre flight list. Each line maps to something one of the two providers states.

• [ ] SPF record on the sending domain lists every service that sends as that domain.
• [ ] DKIM is on, with a 2048 bit key if your provider offers it (Google's minimum is 1024).
• [ ] DMARC record is published, at least p=none, with a rua address so you receive reports.
• [ ] The From domain aligns with the SPF or DKIM domain.
• [ ] Unsubscribe line and the one click headers are on for the mailbox.
• [ ] You have a way to act on an unsubscribe within 2 days, and in practice before the next email goes out.
• [ ] You have registered the domain in Google Postmaster Tools, so you can see the spam rate Google reports.
• [ ] Your send volume per mailbox is small and ramps up slowly.
• [ ] Your list is checked for invalid addresses before sending, because bounces hurt reputation. This one is general practice, not a line on the two pages.

The first four are DNS and configuration work you do once. The rest are habits.

Where does Sellinger fit?

Sellinger does not provide deliverability tooling. It does not check your DNS records, run inbox placement tests or monitor your domain. You or your IT provider set up SPF, DKIM and DMARC at the domain, and you watch Postmaster Tools yourself.

What the product does enforce sits in the sending behavior and is listed on the outreach rules page:

• Daily limits per mailbox. Email defaults to 50 sends a day per mailbox. An account can carry its own value.
• Optional warm up. It starts at 5 sends a day and doubles every 3 days up to the limit. It is optional, so turn it on for a new mailbox.
• Suppression list. Before every send the platform checks the team's suppression list and refuses the send if the contact is on it or if the check cannot be completed.
• Opt out replies. When a contact replies with a clear opt out such as STOP or unsubscribe, the contact goes on the suppression list, the agent stops and the lead is closed out. A weak or unclear phrase never writes the permanent record: the agent stops and a person decides.
• Sending hours. Sending follows the days, hours and time zone you set. Without a schedule, a quiet window of 01:00 to 08:00 local time applies.
• Unsubscribe line and headers. Optional, per mailbox, off by default.

These settings reduce the chance that you send the volume or the repeats that draw complaints. They do not replace authentication, and they cannot make a bad list good.

What do real email programs look like at low volume?

The Shelly installer programme emailed 3,940 installers over about five months, and the agent sent the first email plus up to two follow ups after Shelly capped the sequence. The two stop complaints in that study came from touches 4 and 5, which is the sort of signal that shows up in complaint rates at scale. The study makes no claim about spam rates or inbox placement, and we did not measure them there.

The lesson for a sender is modest. A short sequence to a list that fits the offer produces few complaints. A long sequence to a poor list produces many. The DNS records get you through the door. What you write and who you write to decide what happens next. For more on that, see does cold email still work and the cold email glossary entry.

What this post does not cover

Neither provider page we read tells you your reputation score, how long a reputation takes to recover or what an inbox placement test would show. Do not read the lists above as a guarantee. Providers can change these rules, so check the two pages linked here before you rely on a number. We last read both on 19 October 2026.

This is not legal advice. The provider rules are about delivery. Whether you may send a cold email at all is a legal question that depends on the country. See is cold email legal.