What is Sending Domain?
Definition: A secondary domain set up specifically for cold email outreach, protecting the company's primary domain reputation from the deliverability risks of high-volume sending.
Your primary domain (company.com) is sacred. If it gets blacklisted, your team's regular business emails stop reaching customers. GTM Engineers set up secondary sending domains for all cold outreach to isolate that risk.
Common naming patterns: getcompany.com, trycompany.com, company.io, usecompany.com. Buy 3-5 of these, set up proper DNS records (SPF, DKIM, DMARC), create 2-3 email accounts on each (john@getcompany.com, john@trycompany.com), and warm them all up. If one domain gets flagged, you rotate to the others while it recovers.
DNS configuration matters. SPF records tell receiving servers which IP addresses can send from your domain. DKIM adds a cryptographic signature to prove the email wasn't modified in transit. DMARC defines what happens when authentication fails. All three must be configured correctly or you'll land in spam regardless of your email content.
Budget for $10-$15 per domain per year from Google Domains, Namecheap, or Cloudflare. Google Workspace or Outlook 365 accounts cost $6-$12/user/month. For a 10-inbox setup across 3 domains, you're looking at $60-$120/month in infrastructure costs. That's trivial compared to the pipeline it generates.