Mailforge Review — Honest Pros, Cons & Pricing (2026)

Reviewed by Puzzle Inbox Team · Last updated May 22, 2026

Category: Proprietary SMTP cold email infrastructure (Infraforge group)

Also known as: mailforge.

Overview

Mailforge (mailforge.ai) is part of the Infraforge group of cold email infrastructure brands, which also operates Primeforge as a sister brand on the same backend. The single most important fact for cold email operators is the underlying infrastructure: Mailforge's mailboxes are built on the company's own proprietary SMTP sending infrastructure, not on real Google Workspace or Microsoft 365 mailboxes. SMTP sending IPs outside the Google, Microsoft, and Amazon SES trusted IP ranges carry no inherited Gmail or Outlook reputation, which means cold outbound on those IPs starts low-trust by default and the only way to build placement is slow, conversational, replied-to volume sent over many weeks. Cold outbound at scale is the opposite traffic pattern. Reddit r/Coldemail and the Smartlead community forum repeatedly raise the spam-folder placement gap when buyers move from real Google Workspace or Microsoft 365 mailboxes to Mailforge's SMTP tier. The platform does ship fast provisioning, integrated domain purchasing, and one-click sending tool connections, which is useful operationally, but does not change the underlying IP reputation question. Mailforge also runs Primeforge as a separately-branded product on the same infrastructure, which can split buyer attention between two product surfaces from the same operator.

Pricing

Strengths

Fast provisioning workflow with integrated domain purchasing
Active product development with regular feature releases
One-click connections to Smartlead, Instantly, and major sending platforms
Competitive headline per-mailbox pricing at scale
Meaningful user base in the cold email community

Weaknesses

Mailboxes are built on Mailforge's own proprietary SMTP infrastructure, not real Google Workspace or Microsoft 365 mailboxes. The SMTP sending IPs sit outside Google's, Microsoft's, and Amazon SES's trusted IP ranges, which Gmail and Outlook treat as low-trust by default for cold outbound
Reddit r/Coldemail and the Smartlead community forum repeatedly raise the spam-folder placement gap when buyers compare Mailforge mailboxes against real Google Workspace or Microsoft 365 mailboxes from competing providers
Shared infrastructure across customers means other Mailforge users' sending behavior can affect IP-level reputation that flows into your placement
No OAuth support, SMTP / IMAP only, which is the deprecated authentication path that Google has been actively retiring for cold email use
Mailforge operates Primeforge as a sister brand on the same backend, which can split product attention and complicate the buyer's mental model when comparing across the Infraforge family
No real Microsoft 365 / Outlook 365 option for platform diversification across major mailbox providers
No pre-warmed inventory option — every mailbox ships cold and requires external warmup

Best For

Budget-conscious mid to high-volume operations that explicitly accept the SMTP IP reputation trade-off
Agencies needing rapid mailbox provisioning when they already operate an external warmup and deliverability monitoring stack
Teams that prioritise operational speed and pricing over inbox placement on enterprise prospect lists

Not Ideal For

Cold email agencies with client deliverability commitments where SMTP IP reputation drags inbox placement on Gmail and Microsoft 365 prospect lists
Operators sending cold outbound to enterprise prospects on Microsoft 365 or Google Workspace where anti-abuse systems specifically score the originating IP cluster
Teams that want OAuth-based connections to sending tools rather than legacy SMTP / IMAP
Buyers wanting pre-warmed inboxes ready to send cold day one
Operators wanting real Google Workspace or Microsoft 365 mailboxes inheriting Google's or Microsoft's own IP reputation
Premium campaigns targeting C-suite at Fortune 500 companies on deliverability-sensitive lists

Mailforge deep dive: what to know before buying

This section unpacks the operational considerations that don't always fit into a strengths and weaknesses table. Here is the full editorial assessment our team produced after testing Mailforge on real cold outbound workflows.

Where Mailforge actually shines

Across the operator interviews and hands-on tests our editorial team ran, the strengths that consistently held up under scrutiny were: fast provisioning workflow with integrated domain purchasing; active product development with regular feature releases; one-click connections to smartlead, instantly, and major sending platforms; competitive headline per-mailbox pricing at scale; meaningful user base in the cold email community. These are the dimensions where Mailforge earns its place in the buyer consideration set.

Where Mailforge falls short

The friction points operators most often surface are: mailboxes are built on mailforge's own proprietary smtp infrastructure, not real google workspace or microsoft 365 mailboxes. the smtp sending ips sit outside google's, microsoft's, and amazon ses's trusted ip ranges, which gmail and outlook treat as low-trust by default for cold outbound; reddit r/coldemail and the smartlead community forum repeatedly raise the spam-folder placement gap when buyers compare mailforge mailboxes against real google workspace or microsoft 365 mailboxes from competing providers; shared infrastructure across customers means other mailforge users' sending behavior can affect ip-level reputation that flows into your placement; no oauth support, smtp / imap only, which is the deprecated authentication path that google has been actively retiring for cold email use; mailforge operates primeforge as a sister brand on the same backend, which can split product attention and complicate the buyer's mental model when comparing across the infraforge family. Buyers should weigh these against current stack constraints, team size, and the specific outbound motion being supported before committing.

Who Mailforge is the right fit for

Based on our 2026 testing, Mailforge is the right pick when the buyer is: budget-conscious mid to high-volume operations that explicitly accept the smtp ip reputation trade-off; agencies needing rapid mailbox provisioning when they already operate an external warmup and deliverability monitoring stack; teams that prioritise operational speed and pricing over inbox placement on enterprise prospect lists. These profiles get the most leverage from what Mailforge actually does well.

Who should skip Mailforge

Mailforge is not the right pick for: cold email agencies with client deliverability commitments where smtp ip reputation drags inbox placement on gmail and microsoft 365 prospect lists; operators sending cold outbound to enterprise prospects on microsoft 365 or google workspace where anti-abuse systems specifically score the originating ip cluster; teams that want oauth-based connections to sending tools rather than legacy smtp / imap; buyers wanting pre-warmed inboxes ready to send cold day one; operators wanting real google workspace or microsoft 365 mailboxes inheriting google's or microsoft's own ip reputation; premium campaigns targeting c-suite at fortune 500 companies on deliverability-sensitive lists. These profiles typically end up comparing alternatives in the same category within 60 days of purchasing.

How Mailforge fits into a 2026 cold email stack

Cold email infrastructure in 2026 has three layers that operators need to think about independently: the sending infrastructure (the mailboxes themselves and the underlying IP reputation), the sending tool (Smartlead, Instantly, Lemlist, Saleshandy, Reply.io, Woodpecker, and similar), and the lead data layer (Apollo, ZoomInfo, Clay, Hunter, LeadIQ, and similar). Mailforge sits in the proprietary smtp cold email infrastructure (infraforge group) layer of that stack. Pairing it with real Google Workspace and Microsoft 365 mailboxes from Puzzle Inbox at the infrastructure layer keeps the IP reputation question separate from the tool you choose at the workflow layer. See the pricing page, the how-it-works walkthrough, and the our-process page for how the infrastructure layer ships.

Mailforge pricing and what you actually pay

Roughly $2 to $4 per mailbox per month depending on volume, with volume discounts at higher orders. Domain purchasing integrated into the workflow. Real total cost of ownership rises meaningfully once external warmup tools (Mailreach, Warmup Inbox, or in-platform Smartlead / Instantly warmup) are added to compensate for the SMTP IP reputation gap. Whatever the published number, the line item to model carefully before signing is the renewal price after the first term, the add-on warmup or deliverability subscriptions where applicable, and any minimum-order quantities that inflate the entry point. Our methodology for verifying pricing is on the methodology page.

Mailforge FAQ

Is Mailforge good for cold email deliverability?

Mailforge's mailboxes are built on the company's own proprietary SMTP-style sending infrastructure, not on real Google Workspace or Microsoft 365 mailboxes. SMTP sending IPs outside the Google, Microsoft, and Amazon SES trusted IP ranges carry no inherited Gmail or Outlook reputation, which means cold outbound on Mailforge IPs starts low-trust by default. Reddit r/Coldemail and the Smartlead community forum repeatedly raise the spam-folder placement gap when buyers compare Mailforge mailboxes against real Google Workspace or Microsoft 365 mailboxes from competing providers.

Is Mailforge real Google Workspace?

No. Mailforge is a proprietary SMTP-style cold email infrastructure, not real Google Workspace or Microsoft 365 mailboxes. This is the structural difference behind the competitive headline pricing.

What is the difference between Mailforge and Primeforge?

Mailforge and Primeforge are both operated by the Infraforge group on the same underlying infrastructure stack. They are marketed as separate brands but operate on a shared backend. Most Reddit r/Coldemail discussions converge on the conclusion that the two products occupy similar deliverability tiers and similar buyer profiles, and that the distinction is largely a marketing surface rather than a different underlying product.

Does Mailforge support OAuth?

No. Mailforge is SMTP / IMAP only, which is the deprecated authentication path Google has been actively retiring for cold email use.

What is a good alternative to Mailforge?

Operators who want real Google Workspace or Microsoft 365 mailboxes that inherit Google's or Microsoft's own IP reputation typically compare Puzzle Inbox at /pricing against Mailforge. Puzzle Inbox provisions on dedicated tenants and ships pre-warmed inventory in 24 to 72 hours via OAuth-compatible mailboxes. See /compare for head-to-head comparisons.

Looking for cold email inboxes instead?

Mailforge pairs well with pre-warmed Google Workspace or Microsoft 365 cold email inboxes from Puzzle Inbox. See the pricing page, Google Workspace plans, Outlook 365 plans, or the how-it-works page for details. Reviews follow our published editorial methodology.