Free Email Warmup Tools: What's Actually Free in 2026

This guide compares free email warmup tools by what you actually get for free: free plans, one-time quotas, trials and warmup bundled with a paid sender. Updated 2 Nov 2026, with every limit checked on each tool's pricing page that day.

Disclosure: we make Alien Mail, which is one of the tools below. Every other tool's limits come from its own pricing page, checked on 2 Nov 2026.

The short answer: 4 tools have a free warmup plan with no time limit: Alien Mail, TrulyInbox, Warmup Inbox and Mailflow. Only Alien Mail warms unlimited inboxes for free. The other 3 cap you at 1 inbox or a few emails a day. Snov.io gives a one-time 450 free warmup emails, Warmy.io and Mailivery are 7-day trials, and Instantly, Smartlead, Saleshandy, lemlist and QuickMail include warmup only in paid plans.

Free email warmup tools at a glance

Per inbox per month = daily limit × 30. Prices are monthly billing, checked 2 Nov 2026.

Capped free plans send 64 to 300 warmup emails a month, against the 900 to 1,200 a new inbox ramps up to.

Truly free email warmup tools

A truly free tool keeps warming with no time limit and no card on file. 4 tools do that, but 3 of them cap you so low that a cold email inbox never reaches a healthy volume.

1. Alien Mail: free warmup for unlimited inboxes

Alien Mail warms every connected inbox for free, with no time limit and no inbox cap. Warmup emails don't use sending credits; you only pay when you send cold emails, from about $1.20 per 1,000 emails at volume. Alien Mail raises each inbox's daily volume as it earns trust, so you don't set a schedule. It's the only free option built for teams warming more than one inbox.

• Best for: cold email senders with 2 or more inboxes who don't want a separate warmup bill

• Watch out for: warmup runs inside Alien Mail, so it suits people who also send their cold email there

2. TrulyInbox: free forever for 1 inbox

TrulyInbox's free plan warms 1 inbox at 10 warmup emails a day with no card. It has no advanced settings, no custom schedule and self-serve support only. Starter is $29 a month for unlimited inboxes sharing 200 warmup emails a day.

• Best for: keeping one existing, healthy inbox active

• Watch out for: 10 a day won't warm a brand-new domain in 3 to 4 weeks

3. Mailflow: up to 100 addresses at 5 emails a day

Mailflow's Free Pool warms up to 100 email addresses at 5 warmup emails a day each. New accounts start with a 14-day trial; to keep warming after it, you switch to the Free Pool. Paid pools are $49 a month (30 a day) and $99 a month (50 a day), each for up to 100 addresses. QuickMail users get Mailflow warmup through QuickMail.

• Best for: keeping many idle addresses active

• Watch out for: 5 a day is too little to warm a new domain for cold email

4. Warmup Inbox: unlimited inboxes at 15 emails a week

Warmup Inbox's Freemium plan is $0 for unlimited inboxes, but each gets only 15 warmup emails a week, about 64 a month. Its Basic plan is $15 per inbox a month for 75 warmup emails a day, with a 7-day trial of the paid plans.

• Best for: keeping many idle inboxes from going cold

• Watch out for: 15 a week is a keep-alive level, not a warmup

Free trials and one-time free quotas

A trial or a one-time quota gives you the product for a short time, then stops. A new domain needs 3 to 4 weeks of warmup, so these show you the product but won't finish warming an inbox.

Snov.io: 450 free warmup emails, once

Snov.io's free Trial plan includes 1 warmup slot at 15 warmup emails a day, up to 450 in total. Snov.io says the 450 doesn't renew when the free plan rolls into the next month, so it covers about 30 days of warmup, once. Starter ($39 a month) adds 3 inboxes at 50 emails a day each.

Warmy.io: 7-day trial, no card

Warmy.io has a 7-day trial with no card, then plans from $49 a month, priced by warmup volume rather than per inbox. It also offers free single-use tools such as a deliverability test, a blacklist checker and an SPF checker.

Mailivery: 7-day trial

Mailivery has a 7-day trial on its plans. Starter is $29 a month for unlimited mailboxes sharing 200 warmup emails a day, at up to 100 a day per mailbox.

Warmup included with a cold email tool

If you already pay for a cold email tool, check its plan before buying warmup. These 5 include warmup in every paid plan, so warmup costs you nothing extra.

Free plan, free trial or bundled: which should you pick?

Pick by how many inboxes you warm and whether you already pay for a sending tool. One inbox fits a capped free plan; 2 or more need unlimited free warmup or warmup bundled with your sender.

• You already pay for a cold email tool: use its built-in warmup. A second warmup tool on the same inbox can double your daily volume and look unnatural.

• You warm 1 inbox and send little: TrulyInbox's free plan (10 a day, no time limit) is enough to keep it active.

• You warm 2 or more inboxes: Alien Mail is the only free option without an inbox cap.

• You're testing a tool before paying: a 7-day trial (Warmy.io, Mailivery) shows the dashboard, but plan a paid month to finish warming.

How does an email warmup network work?

A warmup tool sends a few emails a day from your inbox to a network of real inboxes, which open them, reply and move them out of spam. Gmail and Outlook read those signals as "people want this sender's email" and start trusting your domain.

Each day the tool:

1. Sends a small number of emails from your inbox to other inboxes in the network.

2. Has those inboxes open the emails and reply to some of them.

3. Finds any email that landed in spam and marks it "not spam".

4. Raises your daily volume slowly, usually over 3 to 4 weeks, until the inbox reaches its target.

The network is the product. A free tool with a small network sends from and to the same few inboxes, which filters can learn to spot.

Is free email warmup safe?

Free warmup is as safe as the network behind it, and price has little to do with that. Ask these 5 questions before you connect a real inbox.

1. How big is the network, and which providers are in it? A pool with Google Workspace and Microsoft 365 inboxes matches the people you email. Saleshandy's TrulyInbox pool lists more than 10,000 accounts.

2. Are the inboxes real and in use? Fake or abandoned inboxes send weak signals.

3. Does it rescue emails from spam? Moving emails out of spam is the strongest signal, and some free plans leave it out.

4. Does it report inbox placement, or just a score? You need to see where emails land at Gmail and Outlook, not one number.

5. How does the free plan pay for itself? A free plan that leads to a paid sender (Alien Mail, Snov.io) is normal. One with no clear business model may sell data or shut down.

What does warmup cost once the free part ends?

Warming 5 inboxes costs $0 to $97.50 a month, depending on whether the tool charges per inbox or for a shared volume. Per-inbox pricing gets expensive fastest as you add inboxes.

Shared plans split one daily volume across inboxes: 200 a day across 5 inboxes is 40 each.

How to warm up an email for free without a tool

You can warm an inbox by hand by emailing people who will open and reply, then adding volume slowly. It works for 1 inbox but is hard to keep up across several, because the replies have to keep coming every day.

Set up SPF, DKIM and DMARC before day 1. For the full day-by-day plan, see our email warmup schedule.

What free warmup can't fix

Warmup builds reputation on a healthy setup; it can't repair a broken one. Fix these first, or warmup has nothing to build on:

• Missing SPF, DKIM or DMARC records. Without them, providers can't confirm you sent the email. See SPF, DKIM and DMARC explained.

• A bad list. A high bounce rate can undo weeks of warmup. Verify your list before you send.

• Too much volume too soon. Sending hundreds of cold emails from a new inbox in week 1 outweighs any warmup.

• A blacklisted domain. Get delisted first; see our blacklist removal guide.

• Emails people report as spam. Google's sender guidelines tell senders to keep spam complaints under 0.3%. No amount of warmup outweighs a higher rate.

Free warmup tools that stopped working

• GMass: shut down its free warmup tool after Google told it in fall 2022 to turn off warmup or lose Gmail API access.

• Saleshandy's own warmup: Saleshandy shut down warmup for Google accounts and now provides warmup through TrulyInbox.

If an article still recommends either as a free warmup tool, it hasn't been updated since 2023.

Free warmup in Alien Mail

Alien Mail warms every inbox you connect for free, with no inbox limit and no trial clock. Warmup emails never use credits, and warmup emails never show up in your replies inbox. You pay only for cold emails you send, starting with 100 free credits and no card.

Start free email warmup → · How Alien Mail warmup works

Frequently asked questions

Is there a completely free email warmup tool? Yes. Alien Mail, TrulyInbox, Warmup Inbox and Mailflow have free plans with no time limit. Only Alien Mail has no cap on inboxes; the others allow 1 inbox, or 5 to 15 warmup emails a day or week. Snov.io's free plan includes a one-time 450 warmup emails.

Is free email warmup safe? It's as safe as its network. Check that the network uses real Google Workspace and Microsoft 365 inboxes, rescues emails from spam and reports inbox placement. A small, repetitive network can do more harm than good.

Can I warm up unlimited inboxes for free? Alien Mail warms unlimited inboxes for free. Warmup Inbox's Freemium plan also allows unlimited inboxes, but only 15 warmup emails a week each, which keeps an inbox active without warming it.

How long should free warmup run before I send cold emails? A new domain needs 3 to 4 weeks of warmup before cold sending. Keep warmup running after that, at a lower volume, alongside your campaigns.

Does free warmup work as well as paid? On volume, usually not: most free plans send 5 to 15 emails a day, against 30 to 40 for a full ramp. Free plans also tend to leave out spam rescue and placement reports. Bundled and unlimited free warmup (Alien Mail) remove those limits.

Can I warm up an email without a tool? Yes, by emailing people who will reply and adding volume over 4 weeks. It works for one inbox but is hard to sustain across several.

Does Google allow email warmup tools? Google told GMass in 2022 to turn off warmup that used the Gmail API, and some tools stopped warming Google accounts. Most warmup tools now connect through SMTP and IMAP instead of the Gmail API.

Key terms

• Email warmup: sending a small, rising number of emails that get opened and replied to, so a new inbox earns trust.

• Warmup network (pool): the group of inboxes that exchange warmup emails with yours.

• Spam rescue: moving a warmup email from spam to the inbox, the strongest trust signal.

• Inbox placement: where an email lands, whether inbox, promotions or spam, at each provider.

• Sender reputation: how much Gmail and Outlook trust your domain and inbox, based on how people react to your email.

Related reading

• What is email warmup?

• Best email warmup tools: paid plans compared

• Does email warmup work?

• Email warmup schedule

• Alien Mail vs Warmy.io · Alien Mail vs MailReach