Email warmup, inbox placement tests and mailbox health checks from the Salesforge family, free for one mailbox, unlimited if you subscribe to Salesforge, and $12 a mailbox a month if you do not.
What is
Warmforge
Warmforge warms up cold email mailboxes and shows you where the mail is landing. It exchanges AI-written messages with a pool of real Google and Microsoft accounts, gives each mailbox a Heat Score out of 100, and checks DNS records, MX records and blacklist status on the same screen. It comes from Salesforge, and it is the deliverability corner of that family, sitting next to Mailforge and Infraforge for infrastructure and Primeforge for Google and Microsoft mailboxes. Placement tests send from your mailbox to seeded addresses at Gmail, Outlook, Yahoo and others, then report primary, promotions or spam by provider. Connecting a mailbox is one-click OAuth on Google Workspace and Microsoft 365, and the pool runs on aged accounts with multilingual traffic so the activity reads as ordinary business mail. A feature called Deliverability Boost pulls warmup mail back out of the spam folder to push the filter toward trusting the sender. We would take the free slot and would push back on anyone selling Warmforge as a deliverability plan. Warming a mailbox that sends to a scraped list is theatre, because Gmail and Yahoo moved the gate to a 0.3 percent complaint rate in 2024 and that number comes from recipients your pool will never include.
Integrations and the modern GTM stack
Warmforge connects mailboxes rather than apps, so the integration question is which providers it can warm and what happens when you bring your own SMTP. Two providers connect natively and everything else routes back through the Forge stack.
Google Workspace | The main surface. A mailbox connects through Google OAuth in a couple of clicks with no app password or IMAP credentials involved, and warming starts from a single toggle in the dashboard. The free workspace slot covers one Google mailbox. |
Microsoft 365 and Outlook | The same OAuth flow, Heat Score, health checks and placement tests as Google. These two providers are the entire native list, and Warmforge says the pool itself is dominated by aged Workspace and Microsoft 365 accounts rather than throwaway SMTP senders. |
Salesforge | The sibling sequencer, and the reason the pricing looks the way it does. Any Salesforge subscription from the $40 Pro plan up includes unlimited Warmforge slots, and it extends warmup to mailbox types Warmforge will not touch on its own, including SMTP. |
Mailforge, Infraforge and Primeforge | The infrastructure products in the same family. Mailforge and Infraforge provision domains with shared or private mailboxes, Primeforge sells Google Workspace and Microsoft 365 inboxes, and mailboxes bought in any of them land in Warmforge without a separate purchase of infrastructure elsewhere. |
API, MCP server and CLI | Warmforge issues a self-serve API key and is exposed through the Forge MCP server at mcp.salesforge.ai, which covers warmup stats and placement tests alongside the other Forge products using an X-Warmforge-Key header. Documentation sits at developer.salesforge.ai. |
Free deliverability tools | Salesforge publishes a free inbox placement test, a DKIM checker, an email verifier and a spintax generator on its site. The placement test is the one piece of Warmforge you can run without an account, which makes it a quick read on a domain before you commit. |
What is missing | No native IMAP or SMTP connection, so Zoho, Amazon SES and self-hosted senders need a Salesforge plan or Forge-provisioned mailboxes. There is no Zapier or n8n app, no CRM connection, and no link to Instantly, Smartlead or Lemlist, and that is where most cold email teams send from. |
Pro’s
The free tier is a real one: a warming slot and a placement test that both renew every month, with no card and no trial clock, so you can watch a single mailbox before spending anything.
Warmup, placement testing and DNS or blacklist monitoring arrive in one dashboard, so when a mailbox goes cold you see the symptom and the likely technical cause without opening a second tool.
At $12 a mailbox falling to $6 above a thousand slots it sits well under MailReach at $19.50, and a $40 Salesforge plan makes the slots unlimited, which changes the maths for anyone running a fleet.
There is one warmup pool rather than a premium tier sold as an upgrade, and Warmforge describes it as aged Google Workspace and Microsoft 365 accounts carrying multilingual traffic.
Warmup stats and placement tests are reachable through a self-serve API key and the Forge MCP server, so an agency can pull mailbox health into its own monitoring instead of logging in to check.
Cons
Warmup carries far less weight than the marketing implies. Gmail and Yahoo made a spam complaint rate under 0.3 percent and proper authentication the gate in February 2024, and a pool of accounts that opted in to receive your mail moves neither number.
Native support stops at Google Workspace and Microsoft 365. Zoho, Amazon SES or your own SMTP get warmed only if you buy a Salesforge subscription or move mailboxes onto Mailforge, Infraforge or Primeforge, so the cheap warmup is also a route into one ecosystem.
One free placement test a month tests one mailbox once. Monitoring an actual fleet means the Pro plan at $39 a month for 100 tests or Growth at $169 for unlimited, and that is where the cheap headline stops applying.
Independent evidence is thin for a tool this widely promoted, at roughly 19 reviews on G2 and a dozen on Trustpilot, plus 2.8 out of 5 from six AppSumo buyers who flagged missing SMTP support and bounce-backs generated by warmup mail.
The network is described as millions of businesses and accounts with no published mailbox count behind it, and pool quality is the single variable that decides whether warmup traffic reads as normal to a filter.
Pricing
Free
$0 First workspace only, no card required
One warming slot for a Google or Microsoft mailbox
One inbox placement test, renewing monthly
DNS, MX and blacklist health checks
Warm up slots, monthly
$12 per mailbox/mo Drops to $11 from 11 slots, $10 from 51, and $6 above 1,000
Automated AI warm up with Heat Score tracking
One free placement test per month included
Health checks across every connected mailbox
Warm up slots, annual
$108 per mailbox/yr About $9 a month, and $72 a year per slot from 11 slots up
Same warmup and monitoring as the monthly plan
Quarterly billing sits at $30 per slot per quarter
Cancel anytime, no contract
Placement Tests, Pro
$39/mo $32.50 a month billed annually
100 tests per month
Up to 50 mailboxes per test
Placement split by provider and folder
Placement Tests, Growth
$169/mo $140.80 a month billed annually
Unlimited tests
Up to 250 mailboxes per test
Two months free on the annual commitment
How it fits your stack
Alternatives
At a glance
One free warming slot per workspace
AI-written warmup on aged real accounts
Heat Score out of 100 per mailbox
Inbox placement tests broken down by provider
DNS, MX and blacklist health checks
One-click OAuth on Workspace and Microsoft 365
Unlimited slots on any Salesforge plan
Public API and Forge MCP server access
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