Cold email deliverability checklist: SPF, DKIM, DMARC and more
Short answer
Authenticate every sending domain with SPF and DKIM, publish a DMARC policy (p=none is the minimum), keep complaints under 0.3% and bounces low by verifying every address, and honour opt-outs quickly. Gmail, Yahoo and Outlook.com now require most of this from anyone sending at volume.
In short
- Gmail (since February 2024) and Yahoo require SPF or DKIM for all senders, and SPF, DKIM and DMARC (at least p=none) for bulk senders.
- Outlook.com moves non-compliant mail from high-volume senders (over 5,000 a day) to Junk from 5 May 2025.
- Keep the spam complaint rate under 0.3% (Gmail recommends under 0.1%) and honour unsubscribes within 2 days (Yahoo).
- Verify every address before sending; a TechSales mailbox is marked at risk from 3% bounces.
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The checklist
- Send from secondary domains (for example a variant of your brand), not your main company domain.
- Publish an SPF record listing the services that send for the domain.
- Turn on DKIM signing in Google Workspace or Microsoft 365 and publish the key.
- Publish a DMARC record, starting with p=none, aligned with SPF or DKIM.
- Warm up each new mailbox before cold sending. See How to warm up a new domain.
- Verify every address before a campaign and keep catch-all results apart. See Catch-all emails.
- Honour opt-outs quickly and watch complaint and bounce rates per mailbox.
What the mailbox providers require
| Requirement | Gmail | Yahoo | Outlook.com |
|---|---|---|---|
| SPF and DKIM | SPF or DKIM for all; both for 5,000+/day | SPF or DKIM for all; both for bulk | Required for 5,000+/day |
| DMARC | Required for 5,000+/day (p=none allowed), aligned | Required for bulk, at least p=none, must pass | Required for 5,000+/day, at least p=none |
| Spam rate | Under 0.3%; recommended under 0.1% | Under 0.3% | Not stated here |
| Unsubscribe | One-click for marketing mail at 5,000+/day | One-click for bulk; honour within 2 days | Visible unsubscribe recommended |
Where TechSales fits
DNS records and warm-up live in your mail provider and your sending tool. TechSales takes care of the list side: two-pass verification before any send, invalid and risky addresses kept apart, opt-out replies put on Do Not Contact and pushed to your sending tool's block list, and Sending health watching bounce rate and warm-up score per mailbox. See Email finding and verification.
Frequently asked questions
- Is DMARC p=none enough?
- It meets the minimum Gmail, Yahoo and Outlook.com publish for bulk senders. Moving to quarantine or reject later protects your domain from spoofing once you are sure all legitimate mail is aligned.
- Do these rules apply to cold email under 5,000 a day?
- The bulk-sender rules start around 5,000 messages a day to a provider, but all senders must authenticate with SPF or DKIM and keep complaints low. Setting up all three records is the safe default.
- Should I send cold email from my main domain?
- It is common practice not to, so that a deliverability problem with outreach does not affect your everyday company email.
Sources
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