Cold email deliverability checklist

1. Domain and mailboxes

• Use a separate domain for outreach, not your main company domain. See secondary domains for cold email.
• Make sure the domain has a simple website or a redirect to your main site, so recipients who check you out see something real.
• Create several mailboxes with real names rather than loading one mailbox.
• Check the domain's history. A domain previously used for spam may already be listed.

2. DNS records

• MX records exist and point to your mailbox provider.
• One, and only one, SPF record, with 10 or fewer DNS lookups. See SPF lookups.
• DKIM signing is set up for your own domain on every service that sends as it. See DKIM in Google Workspace.
• A DMARC record at _dmarc with at least p=none and a working rua address. See DMARC for cold email.
• Run the free checker to confirm all of the above.

3. Sending infrastructure

• Confirm the From domain aligns with the SPF or DKIM domain.
• Check that any tracking or link domain you use is on your own domain, and not shared with thousands of other senders, if your tool offers that option.
• Consider turning off open tracking and link tracking, which add pixels and redirects that some filters dislike. Decide based on your own tests.
• Send a test to Gmail, Outlook and Yahoo accounts you own, and read the Authentication-Results header.

4. Warm-up and volume

• Ramp gradually from a low number and keep volume steady. See the warm-up guide.
• Keep per-mailbox volume modest, and add mailboxes rather than pushing each one.
• Do not send large bursts after days of silence.
• Cut back immediately if bounces or deferrals rise.

5. List quality

• Verify addresses before sending, and remove those that are invalid or risky.
• Avoid purchased or very old lists, which are more likely to contain spam traps and dead addresses.
• Target people who plausibly have the problem you solve. Relevance reduces complaints.
• Suppress anyone who bounced, replied with a request to stop, or unsubscribed, across all your campaigns and mailboxes.

6. Message

• Keep it short, plain and specific to the recipient.
• Use few links, no attachments and minimal formatting.
• Be accurate about who you are and why you are writing. Misleading headers or subject lines are not only bad for deliverability, they are prohibited under laws such as CAN-SPAM in the US.
• Include a clear way to opt out, and honor it quickly.

7. Compliance basics

Rules differ by country. In the US, CAN-SPAM applies to commercial email and requires, among other things, accurate sender information, a non-deceptive subject line, a valid physical postal address and a working opt-out that you honor within 10 business days. Other regions, such as the EU and Canada, are stricter about consent. Gmail and Yahoo also expect bulk senders to support easy unsubscribe and to honor requests within two days. This is general information, not legal advice, so check the rules for the regions you send to.

8. Monitoring

• Set up Google Postmaster Tools for each sending domain.
• Watch bounce rate, complaint rate and reply rate every week. See the complaint rate guide.
• Check blocklists regularly. See checking if your domain is blacklisted.
• Re-check DNS after any change to your tools, because an added service can quietly break SPF or DKIM.

Manual checks work, but they depend on you remembering. OutboxWatch's paid plans are built to run those DNS and blocklist checks every day and alert you when something changes. The free checker covers a one-off look.

If results drop

Start with why your cold emails are going to spam, which walks the same list as a diagnosis, in order of how cheap each thing is to fix.