How many mailboxes per domain?

The rule

Five mailboxes per domain is the recommendation and the balance point: enough that the domain carries useful volume, few enough that losing it to a filter does not take the whole campaign with it. The mailbox form suggests a number at or within one of five, varied a little from domain to domain so a fleet is not exactly five everywhere. One mailbox is fine. Twenty on a two-week-old domain is how you get the whole name filtered together.

EmailPal will let you provision more than five on a domain you register or connect. The mailbox form only warns once a domain would pass about ten, and nothing blocks it. That is a reputation choice, not a feature. Providers correlate mailboxes on the same domain. If one address earns spam complaints, the siblings feel it.

Volume comes from more domains, not from stuffing one name. Fifty mailboxes at 15/day is 750 sends, spread across 10 domains at 5 inboxes each, not one. Warming runs alongside on every inbox (about 20 messages a day) and does not count toward the 15.

Why not more

Inbox providers do not score each address in isolation. They see:

• The domain's age and DNS
• How many identities on that domain started sending at once
• Bounce rate and complaint rate across those identities
• Whether the copy is identical from every mailbox on the same hour

A tiny company does not have 20 people named jane.a through jane.t. Twenty handles on a new .xyz looks like infrastructure, which is what it is. Filters are built to notice that.

Spreading volume across domains is cheaper than "fixing" a domain you overloaded. A burned name is a burned name. How to check and improve your domain reputation.

Caps that interact with the count

Sending limits per mailbox. Warming traffic does not count against these caps.

Plan mailbox math: Starter includes 50 mailboxes. At 5 per domain that is 10 sending domains, which is why Starter also includes 50 domain slots.

Pre-warmed listings

You claim whatever mailboxes are already on that domain. You cannot add extra handles afterward. The bundle was named before it hit the shelf so it reads as one company.

That is why a listing might show three inboxes, not five, and why the dashboard claims a domain as a set. Pre-warmed vs fresh mailboxes and How to claim pre-warmed inboxes.

Fresh domains you register or connect

Create mailboxes on a domain you registered or brought:

1. Wait for DNS to verify.
2. Pick a naming pattern (first, first.last, firstlast, flast).
3. Create 5, not 20.
4. Turn on warming. Do not launch all five into campaign volume on the same morning even after campaign-ready — stagger copy and hours.

Register a domain or Bring your own domain. Names with "mail", "outreach" or "blast" in them get flagged before you send a word.

FAQs

Can I put 10 mailboxes on a domain if I only send 5/day each?

You can provision them. It is still more identities than a tiny company usually has. Prefer fewer mailboxes that actually send over empty ones sitting on the name. Empty warmed mailboxes are still identities on the domain.

Does EmailPal block creating more than the suggested number?

No, not on domains you register or connect. The form suggests about five (recommended: 5) and warns past about ten, but nothing is enforced. Pre-warmed bundles are a fixed set. The guidance is deliverability advice, not a UI lock.

How many domains do I need for 500 sends/day?

At the recommended 15/day per inbox you need about 34 mailboxes. At 5 per domain that is about 7 domains. More inboxes, not a higher cap.

Should every mailbox on a domain send the same copy?

No. Identical bodies from every handle on the same hour is one of the tells. Vary the first line. Stagger send windows.

Need more help?

Domains and mailboxes or the cold email deliverability guide.