Inbox types
Maildeck builds four kinds of inboxes: Outlook, Outlook Premium, Google Workspace and SMTP. They differ in how many inboxes you get per domain, how many cold emails each inbox can safely send a day, and what you can put in your emails. Most people use a mix, which is what the Diversified Stack gives you.
At a glance
Section titled “At a glance”| Inbox type | Inboxes per domain | Safe cold emails per inbox per day | Strengths | Use it for |
|---|---|---|---|---|
 Outlook | Up to 100 (one tenant = one domain) | 10 | Lots of inboxes from one domain, on Microsoft’s trusted infrastructure. | Volume on a budget. |
| Outlook Premium | Up to 100 (one tenant = one domain) | 12 | Same Microsoft infrastructure, more sends per inbox. | Your main volume. It’s the Outlook used in every Diversified Stack. |
 Google Workspace | 5 | About 20 | The most widely trusted provider, and more relaxed about links and tracking. | Your most valuable prospects. |
 SMTP | 5 | 8 | The cheapest inboxes. | Extra capacity next to Outlook and Google, never on its own. |
These daily numbers are safe limits, not targets. Sending more from each inbox is the fastest way to damage a domain. To send more, add inboxes. See Sending limits.
Outlook and Outlook Premium
Section titled “Outlook and Outlook Premium”Outlook inboxes come as tenants: one Microsoft 365
account on one of your domains, with up to 100 mailboxes. That makes Outlook the most domain-efficient choice: one domain
gives you up to 100 inboxes, where Google or SMTP would need 20 domains for the same number.
- Outlook (sometimes called Outlook Normal) is the budget option.
- Outlook Premium runs on the same infrastructure but can safely send more per inbox.
- Outlook Mixed is a blend of Normal and Premium tenants. We pick the mix for your setup.
Outlook is strict about what’s in your emails. Plan your copy around it: no links, no images, no open tracking, no pricing or ”$” language, around 50 words, and varied wording. Writing for Outlook explains each rule.
Google Workspace
Section titled “Google Workspace”Google Workspace inboxes are real Google accounts, the same kind
many of your prospects use. Google is the most widely trusted email provider, so these inboxes suit the prospects where
one reply matters most. You get 5 inboxes per domain, so you need more domains to scale. Google is also more relaxed
than Outlook about links and open tracking.
You can buy Google on its own (per inbox, or as a Google Workspace Starter, Growth or Enterprise plan) or as part of a Diversified Stack.
SMTP inboxes run on private mail servers rather than Google or
Microsoft. They are by far the cheapest per inbox, but they don’t start with the built-in trust of the big providers,
so they build reputation more slowly. Use them to add capacity next to Outlook and Google, for lower-priority prospects
or for testing new copy. Don’t make SMTP your only inbox type. You get 5 inboxes per domain.
Which should I pick?
Section titled “Which should I pick?”- Not sure: start with a Diversified Stack. It mixes Premium Outlook, SMTP and Google for you.
- You want the most volume per domain: Outlook Premium.
- You’re targeting a small number of high-value prospects: Google Workspace.
- You need cheap extra capacity: add SMTP to an existing Outlook or Google setup.
Pricing lists the price of each type, and Choosing a plan works out how much you need.