Compare/Head to head

InboxKit vs Zapmail

Same facts, side by side: starting price, free tier, MCP, API and what each one is actually built for.

Starting price

InboxKit

$2.50/mailbox/mo

US-IP Google Workspace and Microsoft 365 mailboxes for cold email, with SPF, DKIM and DMARC set up for you and export to 24+ sequencers. One flat rate per mailbox: $3.00 a month, or $2.50 on annual billing, with no plan or minimum.

Where InboxKit fits

Agency recruiters sending cold email to hiring managers at volume
Teams already sequencing in Instantly, Smartlead, Lemlist or Apollo
Teams that want to automate mailbox setup through an API

Zapmail

$39/mo

Google Workspace and Microsoft 365 mailboxes for cold email. Starter is $39/mo for 10 Google mailboxes.

Where Zapmail fits

Freelancers starting with 10 Google inboxes
Agencies that want pre-warmed Workspace accounts
Teams exporting to Instantly or Smartlead
Senders who need one domain per workspace

At a glance

Detail	InboxKit	Zapmail
Starting price	$2.50/mailbox/mo	$39/mo
Free tier	–No	–No
MCP server	–No	–No
Public API	✓Yes	✓Yes
Listed under	Deliverability	Deliverability

Where they pull apart

InboxKit

Stands out: Each domain gets its own isolated admin panel, so one damaged domain does not drag the others down. A full REST API with webhooks lets agencies provision mailboxes automatically when a new client signs, and an Azure option covers up to 100 mailboxes for $30 a month.

Watch out: Warmup is not included: it is a $3 per mailbox a month add-on, more than the annual mailbox price itself. The $2.50 rate needs annual billing, and there is no free trial, though you can start with a single mailbox. The 90%+ inbox placement figure is the vendor's own claim.

Not the right fit for

Recruiters sending a handful of emails a day from their own inbox
Teams that want warmup and sending included in one price

Zapmail

Stands out: Pre-warmed US/EU Google and Microsoft mailboxes with automated DNS and OAuth export to sequencers.

Watch out: API access starts on Pro at $299/mo. Extra Google mailboxes cost $3.50 each on Starter.

Not the right fit for

Buyers who need API access on Starter
Teams that want dedicated SMTP IPs they control

Pros and cons

InboxKit

Same price for Google and Microsoft mailboxes
No plans, slots or minimums
Full API with webhooks

Warmup costs extra
No free trial
No sequencer of its own

Zapmail

Starter $39/mo for 10 mailboxes
Pre-warmed Google and Microsoft
OAuth export to major sequencers

API only on Pro at $299/mo
No published free trial
Extra Starter mailboxes are $3.50

What each one costs

InboxKit

$2.50/mailbox/mo

InboxKit charges one flat rate per mailbox, with no plans, no minimum and no base fee. Google Workspace and Microsoft 365 mailboxes cost the same: $3.00 a month on monthly billing, $2.70 on quarterly and $2.50 on annual. Azure is billed per tenant at $30 a month for up to 100 mailboxes. Isolated warmup is an add-on at $3 per mailbox a month, and the InfraGuard monitoring add-on has its first month free. You pay from a prepaid wallet. Confirm current terms on the vendor site.

Checked 4 Nov 2026

Zapmail

$39/mo

Starter is $39/month for 10 Google mailboxes, extra mailboxes $3.50. Growth is $99/month for 30, extra $3.25. Pro is $299/month for 100, extra $3.00, and includes API access. All plans billed monthly. Pre-warmed Google and Microsoft accounts. No free trial. Confirm current terms on the vendor site.

Checked 4 Nov 2026

Common questions

Is InboxKit cheaper than Zapmail?

InboxKit starts lower, at $2.50/mailbox/mo against $39/mo for Zapmail. That is the entry plan on each side, so the real number depends on seats and the tier you land on.

Can you try InboxKit or Zapmail for free?

Neither carries a free tier on our listing.

Not the pair you wanted?

All InboxKit alternatives All Zapmail alternatives Every Deliverability tool

Editorial listings, never paid rankings. Prices checked 4 Nov 2026. Confirm current terms on the vendor site. Spot an error?