Your offer can be perfect and still never be read. Since 2024, Gmail and Yahoo require bulk senders to prove who they are, and Microsoft Outlook followed in May 2025. For exporters who rely on cold email to reach distributors and importers, the technical setup now decides whether you land in the inbox, the spam folder or nowhere at all.
This checklist covers what to set up before you send a single sequence. Work through it once per sending domain.
The rules in one table
| Mailbox provider | Who the strict rules cover | What they require |
|---|---|---|
| Gmail (Google) | Senders of about 5,000+ messages a day to personal Gmail addresses, since February 2024 | SPF, DKIM and DMARC; one-click unsubscribe for marketing mail since June 2024; spam rate under 0.3% |
| Yahoo | Bulk senders, since February 2024 | SPF, DKIM and DMARC; one-click unsubscribe; spam rate under 0.3% |
| Outlook (Microsoft) | Senders of 5,000+ messages a day to Outlook.com, Hotmail and Live addresses, since May 5, 2025 | SPF, DKIM and DMARC; a working unsubscribe link; valid From and Reply-To addresses; mail that fails can be rejected outright |
1. Use a separate sending domain
- Register a domain close to your brand, such as
yourbrand-trade.comorgetyourbrand.com, just for outreach. - Redirect it to your main website so buyers who check it land somewhere real.
- Keep your main domain for customer, supplier and invoice email. If outreach ever runs into trouble, your day-to-day email is not affected.
2. Set up SPF, DKIM and DMARC
These three DNS records tell mailbox providers that your emails really come from you. You add them at your domain registrar or DNS host.
- SPF lists the services allowed to send email for your domain. Example for Google Workspace:
v=spf1 include:_spf.google.com ~all. If you also send through a cold email tool, add itsinclude:as the tool's setup guide says. Keep only one SPF record per domain. - DKIM adds a digital signature to every email. Your email provider generates the record; you copy it into your DNS.
- DMARC tells receivers what to do when SPF or DKIM fail. The minimum is a TXT record at
_dmarc.yourdomain.comwithv=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com. Once reports show everything passing, move top=quarantine.
Check your setup with a free tool such as MXToolbox before you send.
3. Make unsubscribing easy
- Put a plain unsubscribe line in every email, for example "Not the right person? Reply 'no' and I will not contact you again."
- If your tool supports it, turn on one-click unsubscribe (the
List-UnsubscribeandList-Unsubscribe-Postheaders). Gmail and Yahoo require it for marketing mail from bulk senders. - Honor every opt-out quickly and add the address to a suppression list in your tool.
A buyer who cannot leave easily clicks "Report spam" instead, and complaints are what hurt you most.
4. Warm up and pace your sending
New domains and new mailboxes have no reputation yet. Sending hundreds of emails from them on day one looks like spam.
- Start with a small daily volume per mailbox and increase it gradually over two to four weeks. Most cold email platforms include automatic warm-up.
- Spread sending across several mailboxes instead of pushing one mailbox hard.
- Send during your buyers' working hours in their time zone, not yours. A sequence to Germany should go out in the German morning.
5. Keep your list clean
- Verify addresses before sending. Bounces are a strong spam signal. Run every list through an email verifier and remove invalid and risky addresses.
- Target people, not inboxes.
info@andsales@addresses are shared, rarely read by decision makers and more likely to report you. - Stop after a few follow-ups. Three or four touches is plenty. Long sequences to people who never replied drive complaints up.
6. Write emails that look like one person to another
- Plain text, no heavy images or attachments in the first email.
- One link at most, and avoid link shorteners.
- Personalize the first line with something specific to the buyer's company or market.
- Use a real name and a monitored reply address. Microsoft requires that your From and Reply-To addresses can receive mail.
7. Monitor and react
- Register your sending domain in Google Postmaster Tools to see your spam rate and domain reputation at Gmail.
- Watch bounce and reply rates in your cold email tool every week.
- If your spam rate climbs toward 0.1%, pause, review your list and copy, and lower your volume before you hit the 0.3% limit.
8. Respect each market's rules
Cold B2B email is treated differently around the world. In the US, the CAN-SPAM Act requires a truthful subject line, your physical business address and a working opt-out. In the EU and UK, contacting business people may be allowed on a legitimate-interest basis in some countries but needs prior consent in others. Canada's CASL is stricter still. Check the rules for each market you target; this guide is not legal advice.
Quick checklist
- Separate sending domain, redirected to your website
- SPF, DKIM and DMARC records pass
- One-click unsubscribe enabled and a plain opt-out line in every email
- Mailboxes warmed up, volume increased gradually
- Every list verified, no shared inboxes
- Plain-text emails, one link, real sender
- Google Postmaster Tools connected, spam rate under 0.1%
Sources
FAQ
Do the Gmail and Outlook bulk sender rules apply to small cold email campaigns?
The strict thresholds apply to senders of about 5,000 or more messages a day to personal Gmail or Outlook addresses. Smaller senders should follow the same setup anyway: mailbox providers judge every sender on authentication and complaints, and passing SPF, DKIM and DMARC is the cheapest way to avoid the spam folder.
Should I send cold email from my main company domain?
Most export teams use a separate but similar domain for cold outreach, for example yourbrand-trade.com, so that a spam problem cannot damage the domain your existing customers and invoices rely on. Point it to your main website and set up the same authentication records.
What spam complaint rate is too high?
Google, Yahoo and Microsoft all name 0.3% as the line you must stay under. Treat 0.1% as your real warning level: above it, delivery starts to suffer even before you hit the hard limit.
Is cold B2B email legal in the EU?
In many EU countries, emailing a business contact can be allowed under the GDPR's legitimate interest basis if the message is relevant to their job and easy to opt out of, but rules differ by country and some require prior consent. This guide is not legal advice; check the rules for each target market.
Silas Xiao
Builds websites, runs Google SEO and LinkedIn outreach for B2B manufacturers selling into Central Asia, Russia, Southeast Asia and the US. Every tool on ExportBench is tested on that day-to-day work before it gets a verdict.
