Compare/Head to head

Mailforge vs Warm Inboxes

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

Starting price

Mailforge

$3/mailbox/mo

Shared-IP cold email mailboxes from $3 per mailbox per month, billed yearly, with a 10-slot minimum.

Where Mailforge fits

Teams starting shared-IP outbound cheaply
Senders who expect some spam complaints
Buyers who want yearly mailbox billing
Shops already in the Forge stack

Cold email sending infrastructure: prewarmed Google, Microsoft 365 and Azure inboxes on free domains that can send the day you buy them, and cheaper fresh inboxes on your own domains for scaling. Fresh inboxes start at $3 a month and prewarmed ones at $8 a month each.

Where Warm Inboxes fits

Agency recruiters launching cold business development email fast
Teams whose sending domains got burned mid-campaign
Desks scaling outreach across many inboxes
Instantly and Smartlead users who want inboxes set up for them

At a glance

Detail	Mailforge	Warm Inboxes
Starting price	$3/mailbox/mo	$3/inbox/mo
Free tier	–No	–No
MCP server	–No	–No
Public API	–No	–No
Listed under	Deliverability	Deliverability

Where they pull apart

Mailforge

Stands out: Automated SPF, DKIM, and DMARC plus mailbox slots you can delete and recreate at no extra cost.

Watch out: Minimum 10 mailbox slots. No free trial. You pay for slots even if some sit empty. Separate from Infraforge and Primeforge.

Not the right fit for

Buyers who need fewer than 10 mailboxes
Teams that want a free trial before buying domains

Warm Inboxes

Stands out: Prewarmed inboxes skip the two to three week warmup, so a recruiting desk can start a business development campaign the same day or swap in fresh senders when a domain burns mid-campaign. The setup is already done: domains, SPF, DKIM, DMARC and forwarding are configured before you log in.

Watch out: Prewarmed inboxes sit on domains the vendor supplies, not your brand, and cost more than double a fresh inbox. Every result on the site comes from the vendor's own customer stories. It is infrastructure only, so you still need a sequencer such as Instantly or Smartlead.

Not the right fit for

Recruiters who only send from their main company mailbox
Teams that want inboxes on their own brand from day one at the lowest price
Buyers looking for a sequencer or lead database

Pros and cons

Mailforge

$3/mailbox/mo on yearly billing
Automated DNS on every domain
Cancel anytime, no contract

10 mailbox slot minimum
No free trial
Empty slots still bill

Warm Inboxes

Prewarmed inboxes send on day one
DNS and authentication set up for you
Same-day replacement inboxes when a domain burns

Prewarmed inboxes use vendor-supplied domains
Results quoted are the vendor's own
Needs a separate sending tool

What each one costs

Mailforge

$3/mailbox/mo

Mailbox slots are $3/month billed yearly, 10-slot minimum. Monthly billing costs more (25 slots $75/month monthly vs $60/month yearly, which is two months free)..com domains $14/year. SSL/domain masking $2/domain/month or $6/domain/year. No free trial. Cancel anytime. Confirm current terms on the vendor site.

Checked 19 Sep 2026

Warm Inboxes

$3/inbox/mo

Prices are per inbox per month. Prewarmed Google or Microsoft inboxes come in packs of 3 with a free prewarmed .com domain at $8 an inbox monthly, $7 on 2-month or $6 on quarterly billing; a prewarmed Azure tenant of 100 inboxes is $69 a month. Fresh inboxes on your own domains need a 14 to 21 day warmup: Google Workspace from $3.50 an inbox monthly (down to $2 yearly at 100+ inboxes) and Microsoft 365 from $3 monthly ($2 yearly). Creating an account needs no card. Confirm current terms on the vendor site.

Checked 19 Oct 2026

Common questions

Is Mailforge cheaper than Warm Inboxes?

Mailforge starts lower, at $3/mailbox/mo against $3/inbox/mo for Warm 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 Mailforge or Warm Inboxes for free?

Neither carries a free tier on our listing.

Not the pair you wanted?

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Editorial listings, never paid rankings. Prices checked 19 Sep 2026. Confirm current terms on the vendor site. Spot an error?