When setting up multiple mailboxes for cold email, we recommend using a mix of mailbox providers rather than relying on a single provider. This helps diversify your sending infrastructure while still prioritizing the mailbox providers that generally offer the strongest deliverability.
Google and Microsoft 365 mailboxes are available through Primeforge, while Mailforge provides SMTP/IMAP mailboxes on shared IP infrastructure.
Google mailboxes generally offer the best deliverability, followed by Mailforge and then Microsoft 365. The recommended mix depends on how many mailboxes you need.
For the best setup, we recommend prioritizing mailbox providers in this order:
7 Google
3 Microsoft 365
10 Google
10 Mailforge
15 Google
10 Mailforge
5 Microsoft 365
20 Google
10 Mailforge
10 Microsoft 365
25 Google
15 Mailforge
10 Microsoft 365
30 Google
20 Mailforge
10 Microsoft 365
35 Google
25 Mailforge
10 Microsoft 365
40 Google
30 Mailforge
10 Microsoft 365
45 Google
30 Mailforge
15 Microsoft 365
50 Google
30 Mailforge
20 Microsoft 365
Google mailboxes generally offer the best deliverability and are considered the strongest option for cold email sending.
Mailforge is the next recommended option. It provides excellent deliverability, particularly when sending to Microsoft mailboxes, where Mailforge can perform even better than Microsoft 365 sending to Microsoft 365.
However, we don't recommend putting your entire sending volume on a single provider. Diversifying your sending infrastructure helps spread your sending across different mailbox providers and infrastructure, which is why the recommended setups don't use 100% Google even though Google is overall prioritized.
Infraforge uses dedicated infrastructure, so it requires more careful management than the other options. It is better suited for experienced users who understand email infrastructure and deliverability and can properly manage their sending setup.
For this reason, we don't include Infraforge in the standard recommended setups above. It can be a good option for users who specifically need dedicated infrastructure and know how to manage it effectively.
