Warmforge Alternative for Mail Merge: Warmuply vs Warmforge

Searching for a Warmforge alternative usually means one of two things. Either you tried Warmforge and it felt built for someone else, or you’re choosing a warmup tool for the first time and want to compare before you pay.

This page compares Warmuply and Warmforge side by side: what each one does, what it costs, which email accounts it supports, and who each one suits best. Warmforge is a good tool, and for some senders it’s the better choice. We’ll say where.

Last checked: October 2026. Warmforge details come from Warmforge’s own website on that date.

Warmuply vs Warmforge at a glance

Warmforge is a warmup and deliverability tool for cold outreach teams, sold per mailbox and free inside Salesforge. Warmuply is a warmup tool for people sending a mail merge from their own Google Workspace address, priced by how many people you want to email in a day.

Email warmup means sending and receiving normal-looking emails from your inbox over time, so Gmail and Outlook learn to trust it before you send in bulk. Deliverability is whether your emails reach the inbox at all.

What does Warmforge do well?

Warmforge is a strong choice if you run cold email at scale. It belongs to the Salesforge family of outreach tools, and its pages make clear it’s aimed at teams warming up many mailboxes for outreach sequences.

Here’s what stands out, based on Warmforge’s own site:

• Low cost per mailbox. At $9 to $12 per mailbox slot a month, warming 10 inboxes costs far less than many per-inbox tools.
• A real free option. One free warming slot for a Google or Microsoft mailbox, plus one free placement test each month.
• Free with Salesforge. Salesforge customers get unlimited Warmforge slots at no extra cost.
• Microsoft 365 support. It warms Microsoft 365 mailboxes as well as Google Workspace.
• Flexible slots. A slot isn't tied to one mailbox, so you can remove an inbox and add a new one without changing your plan.
• A wider toolkit. It offers an API, MCP and command-line access, and says it is SOC 2 compliant, which matters if a security team reviews the tools you connect.
• Spam rescue during warmup. Warmforge says it moves warmup emails that land in spam back out, which signals trust to email providers.

If you manage a cold email operation with lots of inboxes, those features add up.

What does Warmuply do differently for mail merge senders?

Warmuply is built for a narrower job: getting one Google Workspace inbox ready for a mail merge, then keeping it healthy. A mail merge sends one personalized email to many people from a spreadsheet, using tools like YAMM, Gmail’s built-in mail merge, GMass or Apps Script (Google’s scripting tool for Sheets).

Most people sending a mail merge email people every day. What’s new is sending hundreds at once. Warmuply focuses on the questions that come up then:

• “How many can I send today?” Warmuply shows a daily safe-send number. Put that number into YAMM or whatever you use, and the number grows as your inbox warms.
• “Is my domain set up right?” Warmuply checks SPF, DKIM and DMARC and tells you what’s wrong in normal words, with the exact text to paste.
• “Did it land in the inbox?” Placement tests show inbox, Promotions or spam at Gmail, Outlook and Yahoo, and the likely reason if something’s wrong.
• “Am I on a blacklist?” If your domain is listed, you hear the same day, with steps to get off.
• “Do I have to change how I send?” No. Warmuply runs in the background alongside your mail merge tool.

If you use a cold email platform like Instantly or Smartlead, you probably have warmup built in already. Warmuply is for everyone else.

Warmforge alternative pricing: what does each one cost?

The two tools charge in different ways. Warmforge charges per mailbox slot, whatever your volume. Warmuply charges by how many people you want to email in a day, for one sending address.

Warmforge pricing (from Warmforge’s site, October 2026):

Each paid slot includes warmup, health checks and one placement test a month. Warmforge says there’s no contract and you can cancel anytime.

Warmuply pricing:

Every plan includes daily warmup, your safe-send number, domain checks, placement tests and blacklist alerts. There’s a 7-day free trial with no card needed, and you can cancel anytime. Each plan covers one sending address; extra addresses cost more.

What that means in practice:

On price alone, Warmforge costs less per inbox, and its free slot costs nothing. What you pay Warmuply for is a setup made around mail merge: a daily number to send by, plain-English fixes, and checks across Gmail, Outlook and Yahoo in one place.

Which email accounts does each one support?

Warmforge supports more kinds of accounts. Warmuply supports Google Workspace only, for now.

• Warmforge warms Google Workspace and Microsoft 365 mailboxes. Its blog says it also warms IMAP and SMTP mailboxes from Mailforge and Infraforge, two of its sister products. Inside Salesforge, it warms any mailbox you connect.
• Warmuply works with any address on your own domain that runs on Google Workspace, such as you@yourcompany.com. Microsoft 365 and other providers aren’t supported yet.

If your business email runs on Microsoft 365, Warmforge is the one that can help today.

How does each one tell you when it’s safe to send?

Warmuply gives you a number of emails. Warmforge gives you a score.

Warmforge gives each mailbox a Heat Score from 0 to 100. Warmforge says the aim is to get it up to 100, and that the score helps you decide when a mailbox is ready for higher volume. It recommends warming a new mailbox for at least two weeks before reaching out to prospects.

Warmuply shows a safe-send number: how many emails your inbox can safely send today. If it says 80, you send 80 or fewer in today’s mail merge. Most inboxes need around 4–12 weeks before sending at full volume, and you can send during warmup as long as you stay at or below the number.

The difference matters most if you haven’t sent in bulk before. A score tells you the inbox is healthier. A daily number tells you what to type into your mail merge tool. For more on safe daily volumes, see our guide to how many emails you can send a day without landing in spam.

How do the domain checks compare?

Both tools check your domain settings and blacklist status. They differ in how much they explain.

Your domain has settings, stored in DNS (the public settings for your domain, managed where you bought it), that prove your emails really come from you:

• SPF lists which servers may send email for your domain.
• DKIM adds a digital signature to each email so providers can confirm it wasn’t changed.
• DMARC tells providers what to do with emails that fail those checks.
• MX records tell the world where to deliver email sent to your domain.

A blacklist is a list of senders that spam filters treat as risky.

Warmforge’s health checks monitor your SPF, DKIM, DMARC and MX records plus blacklist status, daily, and alert you when something breaks. That suits teams who already know how to fix DNS records.

Warmuply checks SPF, DKIM and DMARC and explains any problem in plain English, with the exact text to paste into your domain settings. Blacklist alerts arrive the same day, with steps to get off the list. You can try the checks now with our free SPF, DKIM and DMARC checker.

How do the placement tests compare?

A placement test sends a test email to accounts at different email providers and reports where it landed.

Warmforge includes one placement test a month with its warmup plan, and reports how many test emails were delivered at each provider, such as Google and Outlook. If you want to test before every campaign, you’ll need a placement test plan: $39 a month for 100 tests, or $169 a month for unlimited tests.

Warmuply includes placement tests on every plan. Each test shows whether your email reached the inbox, the Promotions tab or spam at Gmail, Outlook and Yahoo, and the likely reason if something is wrong. The Promotions tab result matters for a mail merge, because it decides whether your email sits with newsletters or with personal messages.

When is Warmforge the better fit?

Choose Warmforge if any of these describe you:

• You run cold outreach from many mailboxes and want the lowest cost per inbox.
• You already pay for Salesforge, so Warmforge warmup is included.
• Your email runs on Microsoft 365.
• You only need to warm one mailbox and the free slot covers you.
• You want API, MCP or command-line access to manage warmup from your own systems.

When is Warmuply the better fit?

Choose Warmuply if these sound like you:

• You send a mail merge from your own Google Workspace address with YAMM, Gmail’s mail merge, GMass, Google Sheets or Apps Script.
• You want a clear daily number for how many to send, not a score to interpret.
• You’d rather get DNS fixes in plain English with the text to paste.
• You want placement results that include the Promotions tab and Yahoo.
• You want to try everything for 7 days without a card.

If you’re weighing more than these two, our roundup of the best email warmup tools for mail merge senders compares the main options.

What can’t either tool fix for you?

Warmup builds trust in your inbox. It can’t make people want an email they didn’t expect. That’s true of Warmforge, Warmuply and every other warmup tool.

Both tools help with your side of the setup: a sending history, correct domain settings, sensible volume, and early warning when something goes wrong. Three things stay in your hands:

• Who you email. People who don’t expect your email are the biggest risk. Old, bought or scraped lists also bring bounces and spam traps, which are addresses set up to catch senders who don’t check their lists.
• Spam complaints. When people click “Report spam”, your reputation drops fast, even on a well-warmed inbox. Google says to keep the spam rate shown in Postmaster Tools (Google’s free dashboard for senders) below 0.1%.
• What your email says. Pushy subject lines, lots of links, attachments and an identical template sent to everyone all raise the risk. Single words matter less than most people think; they hurt mainly because they make people hit “Report spam”. Our guide to spam trigger words covers what to watch for.

Google also recommends offering an easy way to unsubscribe and honoring every opt-out. For a full walkthrough of getting a new inbox ready, read how to warm up a new Google Workspace email before your first mail merge.

Before you hit send

• Check your domain settings are correct with our free domain checker.
• Keep today’s mail merge at or below what your inbox can safely send.
• Email people who expect to hear from you, and include a simple way to opt out.
• Keep links to one or two and skip attachments.

If you send from Google Workspace, start a free 7-day trial of Warmuply. No credit card needed.