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Cold Email Deliverability Checklist: SPF, DKIM, DMARC and Warm-Up

You can have the perfect list and the perfect message and still land in spam. Deliverability is the plumbing behind cold email: get it right once and every campaign benefits. Use this checklist before you send your first cold email from a new domain.

1. Use a separate sending domain

Don’t risk your main company domain. Many teams register a close variation (for example, getyourbrand.com or yourbrand.co) for outreach, and point it to the main website. If something goes wrong, your primary domain’s reputation stays safe.

2. Set up SPF, DKIM and DMARC

  • SPF lists the servers allowed to send email for your domain.
  • DKIM signs every message, so receivers can verify it wasn’t altered.
  • DMARC tells receivers what to do when SPF or DKIM fail, and sends you reports. Start with p=none, then tighten later.

Google and Yahoo require authentication from bulk senders, and it helps every sender’s inbox placement.

3. Warm up new mailboxes

A brand-new mailbox that suddenly sends hundreds of emails looks suspicious. Start with a handful of emails a day and increase gradually over two to four weeks. Real two-way conversations help the most.

4. Keep daily volumes modest

Spread sending across several mailboxes rather than pushing one inbox hard. Many cold emailers keep each mailbox to a few dozen new contacts per day.

5. Validate every list

Hard bounces are one of the fastest ways to damage a domain. Run every list through email validation, send to valid contacts first, and treat catch-all addresses with care. A common target is to keep hard bounces under about 2%.

6. Write like a person

  • Plain text, short paragraphs, no heavy images or attachments in the first email.
  • One link at most, ideally none in the first touch.
  • Avoid spammy phrases and ALL CAPS.
  • Personalise the first line so every email isn’t identical.

7. Make opting out easy

Include a clear way to opt out (a simple “reply ‘no’ and I won’t email again” works for one-to-one outreach) and honour it immediately. It keeps complaints down and keeps you on the right side of CAN-SPAM, UK GDPR/PECR and similar rules.

8. Monitor and react

  • Watch bounce, reply and spam complaint rates per campaign.
  • Use Google Postmaster Tools to track domain reputation.
  • If bounces spike, pause and re-validate the list before continuing.

Quick checklist

  1. Separate sending domain
  2. SPF, DKIM and DMARC in place
  3. Mailboxes warmed up
  4. Modest daily volume per mailbox
  5. Every list validated
  6. Plain, personal copy
  7. Easy opt-out
  8. Metrics monitored weekly

Start with clean data

Deliverability starts with the list. leadSaler builds targeted B2B lead lists with every email validated, and offers bulk email validation for lists you already have. Request a free sample.

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