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Free email warmup tools: what is actually free

Twenty tools, each checked against its own website on 5 October 2026 and sorted into free plans, trials, paid tools and free offers that have ended. WarmupBay is listed first because it is ours.

Updated 5 October 202612 min read

In short

Free with no time limit, as of 5 October 2026: WarmupBay, TrulyInbox, E-Warmup, Warmerly, AutoMailer and MailFlow. The most common allowance is one mailbox and 10 warmup emails a day.
Trial only: Warmup Inbox, Warmy, Instantly, lemlist and Smartlead. Paid from the first day: MailReach, Warmbox and Mailwarm.
No longer free: GMass shut its warmup down in January 2023, and Mailivery and Mails.ai no longer list the free plans they once had.
WarmupBay is our own tool and is listed first for that reason. It allows one mailbox per account and cannot connect Microsoft 365 or Outlook.com yet, so for those cases another tool fits better.
Every entry links to the tool's own page. Prices and plans change, so check the source before you decide.

As of 5 October 2026, six of the 20 email warmup tools we checked have a free plan with no time limit: WarmupBay, TrulyInbox, E-Warmup, Warmerly, AutoMailer and MailFlow. Two more, Warmforge and MailWarm.io, advertise one free mailbox without stating its limits. The most common free allowance is one mailbox and 10 warmup emails a day. Everything else called "free" is a trial, usually of 7 or 14 days, warmup that comes with a paid sending tool, or an offer that has since ended.

WarmupBay is our own tool. That is the only reason it stands first in the table. We describe it the way we describe the others, limits included. Every other row comes from that tool's own website, read on 5 October 2026 and linked so you can check it.

Free email warmup tools at a glance

The table is sorted by what you can use without paying, not by quality. We did not test how well any of these tools works, and a pricing page cannot tell you that. WarmupBay is at the top because it is ours. The rest follow in the order free plan, trial, paid, ended.

Tool	Status	What is free	Paid from
WarmupBay (ours)	Free plan	1 mailbox, 10 emails a day; 30 with a website badge. No card.	No paid plan
TrulyInbox	Free plan	1 account, 10 emails a day. No card.	$29 a month
E-Warmup	Free plan	1 mailbox, 10 emails a day. No card.	$49 a month
Warmerly	Free plan	1 mailbox, warmup not metered. No card.	$19 a month
AutoMailer	Free plan	25 emails a day per mailbox, Google Workspace and Microsoft 365 only. No card. Mailbox count unclear.	$29 a month
MailFlow	Free plan	Up to 100 addresses, 5 emails a day each.	$49 a month
Warmforge	1 free slot	1 Google or Microsoft mailbox. Volume not stated.	$10 per slot a month
MailWarm.io	1 free inbox	1 inbox. Volume and duration not stated.	$90 a year
Warmup Inbox	Trial only	7 days. No card.	$15 per inbox a month
Warmy	Trial only	7 days. No card.	$49 a month
Instantly	Trial only	14 days, 2 accounts. No card. Part of a sending tool.	$47 a month
lemlist (lemwarm)	Trial only	14 days. No card. Part of a sending tool.	$69 a month
Smartlead	Trial only	Length not stated. No card. Part of a sending tool.	$39 a month
MailReach	Paid	No trial for warmup.	$25 per mailbox a month
Warmbox	Paid	No free plan or trial listed.	$19 a month
Mailwarm	Paid	No free trial.	$69 a month, billed yearly
Mailivery	No longer free	Free Forever plan (10 emails a day) was listed until October 2024. Now a 7-day trial.	$29 a month
Mails.ai	No longer free	Forever Free plan was listed until at least May 2026. The site now shows a different product.	Not applicable
GMass warmup	Shut down	Was free for anyone. Ended 31 January 2023.	Not applicable
EmailWarmup.com	Unclear	Home page title says free; pricing page shows no free plan.	$29 per mailbox a month

The labels: Free plan costs nothing and states no end date; its caps are in the next column. Trial only is free for a set time, then paid. Paid has no free use of the warmup. No longer free and Shut down were free once; the evidence is further down.

Tools with a free plan

WarmupBay

Our own tool, described by the same rules as the rest. It is free and has no paid plan: 10 warmup emails a day, or up to 30 a day for as long as a WarmupBay badge, a link in your website footer, stays visible. No credit card. One mailbox per account.

The limits: Gmail and Google Workspace connect with an app password and other providers over IMAP and SMTP, but Microsoft 365 and Outlook.com cannot be connected yet. There are no deliverability tests and no blacklist monitoring. And it is new. It started in October 2026, so it has no track record to point to. Source: our free plan.

TrulyInbox

The pricing page reads "Free forever for 1 account" and "No credit card": 10 warmup emails a day with basic deliverability tracking. Its FAQ names Gmail, Google Workspace, Outlook.com and Office 365 among the supported providers. Paid plans share one daily volume across unlimited accounts and start at $29 a month for 200 warmup emails a day ($22 a month billed yearly), each with a 7-day trial. Source: TrulyInbox pricing.

E-Warmup

The Free Forever plan covers 1 mailbox and 10 warmup emails a day, plus 5 DNS score tests and 5 inbox placement tests a month. The page says "No Credit Card. No Expiry." The next plan costs $49 a month for 5 mailboxes with up to 150 warmup emails a day each. Source: E-Warmup pricing.

Warmerly

Warmerly combines warmup with a tool for sending cold email. Its Free plan is labelled "Free forever, no card": one email account of your own, with warmup that is not metered and 3 placement tests a month. Campaign sending on that plan is limited to 100 emails a month. The page lists Gmail, Outlook, Microsoft 365 and any IMAP mailbox. Paid plans start at $19 a month for 5 mailboxes, and their 7-day trial needs a card. Sources: Warmerly pricing and its plan documentation.

AutoMailer

AutoMailer is a tool for sending cold email with a $0 plan that it calls a "free forever plan", no credit card needed. Warmup on that plan is capped at 25 warmup emails per mailbox a day, and the pricing table limits it to Google Workspace and Microsoft 365 accounts. One point is unclear: the same page lists no SMTP warmup slots for the free plan and says additional mailboxes cost $1 a month each there, so check how many mailboxes are warmed at no charge. Paid plans start at $29 a month. Source: AutoMailer pricing.

MailFlow

MailFlow lists a "Free Pool" plan: up to 100 email addresses, up to 5 warmup emails a day per address, SPF and DKIM checks, no support. QuickMail, a paid sending tool, uses MailFlow for its warmup and says it is free for QuickMail users. The MailFlow page carries a 2023 copyright line and we did not sign up, so we cannot say how active the pool is. Source: MailFlow plans.

Warmforge

Warmforge's home page offers "1 Free Warming Slot" for a Google or Microsoft mailbox on your first workspace, with one free placement test a month. A slot covers one mailbox; further slots cost $10 a month each, billed quarterly. The daily volume is not stated. The FAQ on the pricing page still says that slots have to be purchased and that there is no free trial, so confirm the free slot when you sign up. Source: Warmforge home page.

MailWarm.io

Not the same as Mailwarm further down; the two are different sites with nearly the same name. MailWarm.io's home page says "Warmup 1 inbox for Free!" but gives no daily volume and no end date for that inbox. Its paid plans are priced per year, from $90 for 50 inboxes. Source: MailWarm.io home page.

Tools that are free for a trial only

These tools are paid; what is free is a test period. In three of them, warmup is one feature of a larger tool for sending cold email, so the price buys more than warmup.

Warmup Inbox

A 7-day free trial without a credit card. After that, the Basic plan is $15 per inbox a month for 75 warmup messages a day. A help article dated 30 January 2025 describes a Free Monitoring plan for cancelled inboxes: 5 emails a day whose landing is reported, without moving them out of spam. That is monitoring, not warmup. Source: Warmup Inbox pricing.

Warmy

A 7-day free trial without a credit card. Plans start at $49 a month and are priced by the volume of warmup emails. Source: Warmy pricing.

Instantly

Warmup is part of Instantly's sending tool and is listed as unlimited on each plan, starting with Growth at $47 a month. The help center describes a 14-day free trial without a credit card, with up to 2 connected accounts, and says that warmup and accounts are paused when it ends. Source: Instantly help center, article dated 24 July 2026.

lemlist (lemwarm)

lemwarm is lemlist's warmup. The pricing page says it is included in all plans. The Email plan costs $69 a month, or $55 a month billed yearly. The trial runs 14 days without a credit card. Source: lemlist pricing.

Smartlead

Warmup comes with every Smartlead plan, starting with Base at $39 a month. The pricing page says all plans come with a free trial and need no credit card to start. It does not say how long the trial runs. Source: Smartlead pricing.

Tools that charge from the first day

MailReach

$25 per mailbox a month for one to five mailboxes, less per mailbox as you add more. MailReach's own comparison article, updated on 10 June 2026, says there is no free trial for warmup. A spam test is free. Source: MailReach pricing.

Warmbox

The Solo plan is $19 a month, or $15 a month billed yearly, for one inbox and 50 warmup emails a day. The pricing page lists no free plan and no trial. A blacklist and DNS checker is free, but that is separate from warmup. Source: Warmbox pricing.

Mailwarm

Starter is $69 a month, billed annually, for up to 50 warmup emails a day. The FAQ on the pricing page says Mailwarm does not offer a traditional free trial. Source: Mailwarm pricing.

Free offers that have ended

Three tools still appear in lists of free warmup tools although the free offer is gone. The evidence is each vendor's own statement or an archived copy of its pricing page.

GMass warmup: shut down in January 2023

GMass ran a free warmup system that anyone could use, including people who were not GMass customers. The company announced the end itself:

We’re shutting down the GMass email warmup system on January 31st, 2023.

In the same announcement, GMass wrote that Google had told it to shut the system down or lose its access to the Gmail API. The old page for the tool is still online and still shows up in search results; it now opens with a notice that the service has ended.

Mailivery: Free Forever plan no longer listed

Mailivery announced a Free Forever plan on 25 January 2024. Archived copies of its pricing page show the plan at $0 with up to 10 emails a day as late as 12 October 2024. In the copy from 5 December 2024 it is gone. Today the pricing page offers a 7-day trial and paid plans from $29 a month, for 200 warmup emails a day shared across unlimited mailboxes. Mailivery's own article on free tools, updated on 1 September 2026, puts it plainly:

Mailivery is not a free warmup tool.

Mails.ai: free warmup plan no longer on the site

An archived copy of the Mails.ai pricing page from 15 May 2026 lists a "Forever Free" plan with unlimited email accounts and unlimited warmup, restricted to Gmail and Google Workspace. On 5 October 2026 the site describes a different product, an email API for AI agents. Its pricing page does not mention warmup, and the home page says cold email is blocked. We found no notice on the site about what happened to the earlier plan.

One tool we could not classify

EmailWarmup.com

The home page title reads "Email Warmup: for FREE + Unlimited Email Spam Tests". The pricing page lists a Pro plan at $29 per mailbox a month with a "Try for Free" button, and an Enterprise plan at a custom price. It shows no $0 plan, and neither page states how long the free use lasts or what it includes, so we mark it unclear.

How to tell a free plan from a free trial

"Free" covers four different things here: a plan that stays free, a trial, a feature inside a paid tool, and an offer that no longer exists. These checks take a minute on any pricing page.

Look for a plan at $0, not a button. A free plan sits on the pricing page as its own plan, with a price of $0 and its own limits. A "Try for free" button next to a price, or "7-day" and "14-day" near the sign-up button, means a trial.
Read "free warmup" in context. On a sending tool it usually means warmup costs nothing extra once you pay for the plan. Instantly lists unlimited warmup on plans from $47 a month, and lemlist says lemwarm is included in all plans.
Ask what "unlimited" counts. It often counts mailboxes, not emails. Saleshandy's pricing page, for example, explains unlimited warm-up as an unlimited number of connected mailboxes, with a daily limit set by the plan.
Find out what happens at the end. Instantly says warmup is paused when its trial ends. If you meant to keep warming while you send, a trial does not cover that.
Check the date of the list you are reading. GMass still appears in lists of warmup tools more than three years after it shut its warmup down.

Which tool fits which situation

WarmupBay is one option among several, and for some situations it is the wrong one.

One mailbox at Gmail, Google Workspace or a host with IMAP, and it should stay free. WarmupBay, TrulyInbox and E-Warmup offer nearly the same: one mailbox, 10 warmup emails a day. WarmupBay goes up to 30 a day with the badge. Warmerly's free plan does not meter warmup at all. E-Warmup and Warmerly add a few placement tests. TrulyInbox, E-Warmup and Warmerly have paid plans if you outgrow the free one; WarmupBay has none. You can start with WarmupBay here.
A Microsoft 365 or Outlook.com mailbox. Not WarmupBay, for now. TrulyInbox names Outlook.com and Office 365 as supported, Warmerly lists Outlook and Microsoft 365, AutoMailer's free warmup covers Microsoft 365, and Warmforge's free slot takes a Microsoft mailbox.
Several mailboxes. WarmupBay allows one per account. MailFlow's free plan allows up to 100 addresses at 5 emails a day each. Among paid tools, TrulyInbox and Mailivery let unlimited mailboxes share one daily volume, from $29 a month.
Placement tests or blacklist monitoring. WarmupBay has neither. E-Warmup's free plan includes 5 inbox placement tests a month, Warmerly's includes 3, and MailReach offers a free spam test next to its paid warmer.
You already pay for a sending tool. Check whether warmup is included before adding another tool. With Instantly, lemlist and Smartlead it is.

How we checked, and what will change

We started from the tools that appear in search results for "free email warmup tool", added others we knew to have a free offer, and opened each tool's own pricing page, help center or announcement on 5 October 2026. For offers that ended, we used the vendor's own announcement or a copy of its pricing page at the Internet Archive. We did not sign up for the other tools, test them or rate them.

Expect these to change first: trial lengths, entry prices, and the caps on free plans, ours included. Two of the three ended offers above disappeared without an announcement we could find. The date at the top of this page is the day every source was last read.

This page compares prices and limits only. Whether mailbox providers allow warmup is covered in Is email warmup allowed?, and what happens to your mailbox inside a shared pool in How email warmup pools work.

Questions people ask

Is there an email warmup tool that is free with no limits at all?

Not among the 20 tools we checked on 5 October 2026. Every free plan caps the number of mailboxes, the warmup emails per day, or both. The most common allowance is one mailbox and 10 emails a day. The widest free offers we found were unmetered warmup on one mailbox at Warmerly, 25 emails a day per mailbox at AutoMailer, and up to 100 addresses at 5 emails a day each at MailFlow.

Is Instantly's email warmup free?

Only during the trial. Instantly's pricing page lists unlimited email warmup as part of its paid plans, which start at $47 a month, and its help center describes a 14-day free trial without a credit card. When the trial ends, warmup and accounts are paused until you subscribe.

Will I be charged if I forget to cancel a warmup trial?

That depends on whether you gave a card. Instantly and Warmup Inbox start their trials without a credit card, and Instantly's help center says there are no automatic charges when the trial ends. QuickMail asks for a card but states that its trial ends without starting a subscription, while Warmerly's paid trial needs a card and charges on day 8 unless you cancel. Read the trial terms of the tool you pick.

Is 10 warmup emails a day enough?

It gives one mailbox a small, steady exchange of mail. Whether that is enough depends on how much you plan to send, and no pricing page can tell you that. For comparison, the paid plans priced per mailbox in this comparison sell between 50 and 1,000 warmup emails a day.

What does email warmup cost once a trial is over?

For a single mailbox, the entry prices we found on 5 October 2026 run from $10 a month (one Warmforge slot, billed quarterly) and $15 a month (Warmup Inbox) up to $69 a month (Mailwarm, billed yearly). Tools that share one daily volume across many mailboxes, such as TrulyInbox and Mailivery, start at $29 a month. Sending tools that include warmup cost, for example, $19 a month at Warmerly, $39 at Smartlead and $47 at Instantly.

Why does a tool appear as free in one list and as paid in another?

Mostly because offers change and lists are not rechecked. Mailivery listed a Free Forever plan in 2024 and now offers a 7-day trial. Mails.ai listed a free warmup plan until at least May 2026 and now shows a different product. Some lists also count a trial, or warmup included in a paid plan, as free. The vendor's own pricing page on the day you look is the answer that counts.