Reputation is tied to the domain. When a cold campaign goes wrong you want it to hit a domain that costs a few pounds a year, not the one with your website, invoices and clients.
The target state for one brand: 2 to 3 secondary domains, 2 to 3 mailboxes on each, all warmed up, in rotation, with a limit of 30 to 50 emails a day. That is 200 to 400 emails a day without risk.
Choose and buy the domains
Variants of your main domain: yourcompany-mail.co.uk, yourcompany-team.co.uk, getyourcompany.com. Avoid leading hyphens and numbers. Set a 301 redirect to your main website so a reader who clicks the domain can confirm you exist.
Create the mailboxes
Google Workspace and Microsoft 365 have the best starting reputation; your own SMTP hosting is cheaper but needs more care. Name mailboxes like real people: martin@yourcompany-mail.co.uk, never info@ or sales@.
Set SPF, DKIM and DMARC
Your mail provider gives you the values; you add them to the domain's DNS. Start DMARC with the "none" policy and move to "quarantine" after a week without errors. The check in Colldly tells you what is missing and the exact value.
Connect the mailboxes to Colldly
Individually or in bulk via CSV. Each one passes an SMTP and IMAP test. Set the daily limit (start at 10), gaps of 3 to 9 minutes and the sender name.
Switch on warm-up everywhere
Two to four weeks. Target daily volume 30 to 40, growth of 2 to 3 a day, reply share 40 to 50%. Watch the score: when it stays above 90% for two weeks, the mailbox is ready.
Collector mailbox and signature
Set reply-to to one collector mailbox per brand so you watch one inbox. Plain-text signature: name, company, phone, postal address (for GDPR and CAN-SPAM). No images.
- 2 to 3 secondary domains redirecting to the main site
- 2 to 3 mailboxes per domain with people's names
- SPF, DKIM, DMARC green in Colldly
- Mailboxes connected, SMTP and IMAP tests passed
- Warm-up running for 14 to 28 days
- Collector mailbox and a plain-text signature