Compare/Head to head

InboxKit vs Premium Inboxes

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

Premium Inboxes

$3.50/inbox/mo

Done-for-you Google Workspace and Microsoft 365 inboxes for outbound sending, from $3.50 per inbox per month.

Where Premium Inboxes fits

  • Outbound recruiting teams that need real Workspace or M365 boxes
  • Agencies standing up client domains
  • Desks that want DNS and warmup handled
  • Buyers who need a public API on every plan

At a glance

DetailInboxKitPremium Inboxes
Starting price$2.50/mailbox/mo$3.50/inbox/mo
Free tier–No–No
MCP server–No–No
Public API✓Yes–No
Listed underDeliverabilityDeliverability

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

Premium Inboxes

Stands out: Official Workspace and M365 inboxes with free replacements and sub-six-hour setup.

Watch out: It supplies the inboxes only. You still need a sequencer to send, and there is no MCP.

Not the right fit for

  • Teams that only need a sequencer, not inboxes
  • Buyers who want MCP

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

Premium Inboxes

  • Official Workspace and M365, not lookalike domains
  • Setup in under six hours
  • Public API on all plans
  • No MCP
  • You still need a sequencer to send

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

Premium Inboxes

$3.50/inbox/mo

From $3.50/inbox/mo. Confirm current pricing on the vendor site.

Checked 4 Nov 2026

Common questions

Is InboxKit cheaper than Premium Inboxes?
InboxKit starts lower, at $2.50/mailbox/mo against $3.50/inbox/mo for Premium Inboxes. 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 Premium Inboxes for free?
Neither carries a free tier on our listing.

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