Domain density

Choose inboxes per domain from send load and risk, not a one-size-fits-all rule.

Inbox density should be planned alongside daily send caps, sequence length, domain reputation, authentication, and readiness evidence.

Use volume to find the constraint

The right inbox-per-domain count depends on more than a preferred density number. Monthly prospects, touches per prospect, send days, per-inbox daily caps, and per-domain daily caps all interact. High daily volume may require more domains even when each domain has only a few inboxes.

  • Estimate required daily sends from campaign volume.
  • Compare daily sends against per-inbox and per-domain caps.
  • Use the stricter constraint when planning domain count.

Keep new infrastructure conservative

New or recently repaired infrastructure should use conservative assumptions. GTM calculators default to cautious caps because a plan that barely fits on paper can fail in production when DNS, seed placement, or mailbox readiness is incomplete.

Review readiness before exports

Even a well-sized domain plan can produce blocked export rows if inboxes lack SMTP readiness, IMAP readiness, credential metadata, or fresh smoke-test signals. Use density planning before provisioning, then readiness reports before campaign setup.

Common questions

Is three inboxes per domain always safe?

No. It can be a conservative starting point in some workflows, but actual capacity depends on volume, daily caps, reputation, authentication, readiness, and seed-placement evidence.

Should I add more inboxes or more domains first?

Use the calculator to find the bottleneck. If domain daily caps are the constraint, adding more inboxes to the same domain does not solve the capacity problem.

Related workflows

Calculate domain count

Model domain count from campaign volume and conservative send caps.

Calculate inbox count

Estimate the number of mailboxes needed for the same campaign plan.

DNS and auth checker

Run a practical check from the guide before approving the next step.

What a launch gate is

The evidence GTM requires before first prospect traffic.

Next step

Plan domains, inboxes, SMTP capacity, and monthly package assumptions together.

Model package capacity