If you want to avoid the spam folder, email warmup is non-negotiable.
Sending from a cold inbox is one of the biggest mistakes in outreach.
If providers don’t know you, your sender reputation stays low. No trust = no inbox access.
To warm up your email properly, you need a warmup tool — most charge a fee.
If you’re on a tight budget, you might look for free email warmup tools.
But what are your options? And should you even use a free warmup tool? We’ll explain below.
Before discussing the drawbacks of free warmup tools, let's run through the free options at your disposal.
We’ll cover both completely free solutions and tools that offer free trials:
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Mails.ai is an AI‑driven cold email outreach platform offering a free warmup plan.
Their free warmup only works for Google Workspace/Gmail accounts, but you can warm up an unlimited number of inboxes.
Limited warmup network
While Mails.ai’s warmup is free and unlimited for Gmail accounts, some users report that the quality of their warmup pool is quite limited compared to paid services. This can make the warmup less effective at getting emails into real inboxes.
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Another 100% free email warmup tool that’s quick to set up and offers warmup for unlimited inboxes.
EmailWarmup.com automatically ramps up the warmup volume with its “Volume Ramp” feature.
Subpar warmup pool
EmailWarmup.com’s warmup pool (the network of inboxes they send warmup emails to and from) is its biggest drawback.
They mainly send warmup emails to private domains instead of major providers like Gmail (Google Workspace) or Outlook (Office 365).
This means you’re not building your sender reputation where it matters most. Most companies use Google Workspace or Office 365, even if their addresses look like: person@companydomain.com.
EmailWarmup.com can still be useful for warming up new inboxes used for newsletters or transactional emails, but its limited pool may not be robust enough for cold email outreach.
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Mailivery is a premium email warm-up tool that's become a go-to choice for agencies and SaaS companies running large-scale cold outreach campaigns.
Mailivery isn’t a completely free warm-up tool. Instead, it offers a 7-day free trial that lets you test drive it for a whole week without paying. The trial includes all features.
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TrulyInbox is an email warmup tool that offers warmup for cold email but also for email marketing services like Mailchimp and GetResponse.
It aims to help improve deliverability across different types of campaigns, whether you’re doing sales outreach or sending newsletters.
Limited warmup emails
With their free plan, you can warm up one inbox and send 10 warmup emails per day. The main culprit is that you only get replies to 10% of your warmup emails, which is too low.
Sending 100 warmup emails and only getting 10 replies does not signal to email providers that your emails offer value. You should aim for at least a 30% reply rate on your warmup emails.
Still, it’s free, so it’s not a bad way to get started. After giving it a try, you can either upgrade to their paid plans, or switch to a more advanced warmup tool.
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Warmy.io is a warmup tool from Israel designed to boost your email deliverability.
Similarly to Mailivery, it’s not a completely free warmup tool, but it offers a free 7-day trial. You can send a limited number of daily warmup emails with it.
Warmy’s setup is easy, making it a beginner-friendly tool and it has decent reporting and automation.
A standout Warmy feature is its two warmup networks: one for B2B and one for B2C. Most tools only cover B2B, so this adds helpful flexibility.
Warmup pool doubts
Warmy is a solid warmup tool if you want something that’s easy to use and offers clear tracking. It can work for solopreneurs having to warm up a single inbox.
But if you’re doing large-scale outreach or managing lots of client inboxes, a tool with a bigger and better warmup pool like Mailivery will give you better inbox placement.
The answer is, unfortunately, no. Some could even hurt your sender reputation if you’re doing cold email.
Here’s why:
Free warmup tools often send and reply to generic messages using a small, low-quality network of inboxes. They typically don’t have the resources or incentives to set up and maintain a high-quality warmup pool.
If you send email newsletters or transactional emails to which people opted in, a free tool might suffice.
But for real cold email outreach, it’s not enough because:
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Email warm-up is a delicate practice. Use the wrong warmup tool, and you will damage your domain reputation.
To pick a tool that will actually help you boost email deliverability, here’s a checklist.
Mailivery ticks all the boxes.
Sign up for a free 7-day trial today (all features included), and start reaching your prospects’ inboxes.
The easiest way to get responses to your cold emails.
