Why it matters
If your emails land in spam, nothing else matters. And a domain that gets a bad reputation can drag down your normal email too, including invoices and replies to customers.
The three DNS records:
- SPF lists which servers may send email for your domain.
- DKIM signs each email so the receiver can check it wasn't changed and really came from your domain.
- DMARC tells receivers what to do when SPF or DKIM fail, and sends you reports.
Google and Yahoo require authentication for bulk senders, and low spam-complaint rates. Beyond the records, reputation comes from behaviour: new inboxes need warm-up, volumes should be modest, lists should be verified so you don't bounce, and you stop emailing people who reply or opt out.
Many teams send cold email from a separate lookalike domain, so problems there never touch the main one.
How Cosmo handles it
Cosmo sends from separate warmed inboxes on a lookalike domain (up to 5 inboxes), checks SPF, DKIM and DMARC before the first send, verifies every address, keeps daily volumes modest, and stops on replies and bounces. Each batch of emails is an approval card. The full setup is in cold email that doesn't burn your domain.