Zapmail alternative: 100 Microsoft 365 inboxes for $30 a month

What 100 mailboxes costs on each

Zapmail’s Pro plan includes 100 mailboxes for $299 a month, which is $2.99 a mailbox, on Google or Microsoft. Their help centre publishes what happens after twelve months on Google: the plan renews at $449 and extra mailboxes move from $3.00 to $4.50. For Microsoft they say renewal "follows its applicable pricing terms" without a figure.

Here, 100 Microsoft 365 inboxes on one domain are $30 a month, in the first year and after it, plus $12 once if we register the domain. Over a year that is $360 against $3,588 for Zapmail Pro, before domains on either side. The comparison is not quite like for like, and the next section is why.

Three per domain against a hundred per domain

Zapmail recommends 3 mailboxes per domain, up to 5. A hundred mailboxes therefore means about 34 domains, each bought, renewed and kept healthy. We put 100 Microsoft inboxes on one domain and size each one at 3 sends a day, so the domain carries 300 a day in total. Both are ways to keep a domain’s daily volume modest; one spreads it across mailboxes, the other across domains.

Which suits you depends on what you are buying for. If you want many independent domains so that one complaint spike touches only three mailboxes, the Zapmail shape fits. If you want daily capacity at the lowest cost per send and fewer domains to manage, 300 sends a day for $30 is $0.10 a month per daily email. Our Google product follows the many-domains shape too, at up to 3 inboxes on a domain. How many cold emails per inbox per day sets out where the per-inbox numbers come from.

Isolation

Zapmail publishes "one domain per workspace" and "workspace-level isolation", and says each mailbox is created inside a genuine workspace tenant. That is the right idea. What their pages do not say in so many words is whether a Microsoft tenant is dedicated to one domain or one customer, which is worth asking, because Microsoft caps external recipients per tenant and complaints attach to the tenant. We provision one Microsoft 365 tenant per domain and never add a second domain to it. Cold email tenant isolation explains what a shared tenant costs.

Warmup and pre-warmed mailboxes

Zapmail sells warmup as Zapwarm, $2.00 a mailbox a month for the first 30 and less above that, with a 21-day ramp for Google and 35 days for Microsoft. They also sell pre-warmed mailboxes that live on Zapmail’s own domains for 12 months and cannot be renewed or refunded. We do neither: we switch warmup on in your sequencer at handover and you keep it running. If you want warmup inside the same bill as the mailboxes, Zapmail does that and we do not.

Where Zapmail is the better choice

• You want Google and Microsoft mailboxes mixed freely under one plan.
• You want warmup, placement testing and pre-warmed mailboxes from the same vendor.
• You export to many tools: they publish one-click export to four sequencers and OAuth to 23 more, plus an API.
• You prefer many domains with a few mailboxes each, and a domain marketplace to buy them in.

Where we are

Price per daily send on Microsoft, a price that does not change after year one, a dedicated tenant per domain stated plainly, and a domain that stays in your name. We sell inboxes and the DNS that decides whether their mail arrives, and nothing else.

What we can show for our own sending: across 11 campaigns on these Microsoft 365 inboxes, 26,698 leads contacted produced a 1.73% bounce rate. Reply rate was 1.9% and ranged from 0% to 4.1% campaign by campaign, because replies depend on the list and the copy, which we do not supply. These are our results, not customer results, and none of it was sent on Google. The full numbers and method are published.