Best Email Warming Tools for Cold Email (2025)

Cold emailing is a double edged sword; on one hand it can help you generate extremely valuable leads with virtually no work, but if it’s not done correctly, your emails can land in the spam folder and all that time can be wasted.

One of the best ways to prepare for a cold email campaign is to warm up your email and domain to increase email deliverability. This used to be done manually by emailing back and forth with your friends, colleagues, and co-workers. The goal is to generate a ton of email activity and positive responses which boosts your domain’s reputation and increases the likelihood that your emails stay out of spam and land in the primary inbox. 

Nowadays, there are a variety of tools that can automate this process and that’s exactly what we’ll be covering today.

Our family at LeadLoft sends a lot of emails, so we’ve had plenty of time to test out nearly all of the email warming tools on the market - here are our 5 favorites. 

Let’s dive in!

What is email warming?

If you're sending a lot of cold emails at some point your sender reputation will decrease. This means fewer emails will land in the recipients primary inbox and instead will land in the spam folder.

To ensure this never happens, you can continuously warm your email using a variety of tools like Warmbox or Warmy.io.

How does email warming work?

Email warming works by sending emails back and forth between your email and other email addresses, carrying out fake conversations. But the magic happens whenever an email you sent lands in the spam folder. When this happens, the receiving email will mark your email as important and as not spam.

This ensures that in the future when you send an email, your email is marked important and not spam - ensuring that it lands in the primary inbox and gets seen.

Now, let's div into the best tools to use to recover and maintain a healthy sender reputation.

1. Warmbox.ai

If a stunning UI and pleasant user experience is your preference, Warmbox.ai is the warm up tool for you. You can connect to a wide variety of email services using Warmbox and it’s spam tests provide enough information for nearly everyone.

Starting Price: $15/mo
Noteworthy Features:

• Beautiful UI & UX
• 4 preset warmup algorithms

2. Warmup Inbox

With 7,000 email addresses in their network, Warmup Inbox is one of the best solutions if you plan on running a long-term warmup campaign. Similar to Folderly, it can automatically adjust the content of emails to make sure they don’t hit spam filters.

Starting Price: $9/mo
Noteworthy Features:

• Largest network of email addresses
• 24/7 Support

3. Glock Apps

Glock Apps is one of the easiest to get started with because they offer a 2 week free trial without requiring any payment info and the trial has nearly all of their features. If you just want to check out how a warm up tool works without any commitment, this is the best option for you.

Starting Price: $59/mo
Noteworthy Features:

• Instant alerts
• Feature-full 2 week trial
• Detailed tests

4. Folderly

Folderly relies heavily on AI to power their warm up tool, creating fake conversations that seem real to any untrained eye. It’s unclear what impact these higher quality conservation have on the effectiveness of their email warming but at the very least, you can be confident that these human-like conversations make Folderly future proof.

Starting Price: $49/mo
Noteworthy Features:

• AI-run for the highest deliverability rates
• Content analysis: Adjusts email content until they aren’t marked as spam

5. Mailwarm

Mailwarm prides itself on its “2 min setup” and it isn’t joking around; this is the easiest and quickest way to warm up your inbox. By mimicking perfect email activity, Mailwarm claims they can boost your open rate by more than 30%.

Starting Price: $79/mo
Noteworthy Features:

• Quickest setup in the industry
• Easy-of-use

Wrapping Up

And there you have it: our top 5 email warmup tools for cold emailing! Best practice for these tools is to run them for about 2 months, but run a test before beginning your warmup so you can gauge your progress throughout the process.

If you’re still struggling to get responses to your cold emails, take a look at our guide for boosting cold email response rates or take a look at our favorite cold emailing tools to automate the process and really scale your outreach!