Email Warm-Up Tools – All You Need to Know

By: Jack Reamer |
 April 27, 2022 |

A hot topic among cold emailers at the moment is “email warming.” 

If it sounds like a night of typing cold emails next to a fireplace with a glass of wine in hand, I’m afraid to disappoint you; it’s not that. BUT email warm-up tools can really ramp up your outreach campaigns. 


If you’re interested in finding out more, keep reading as we discuss what email warm-up tools are, how they work, if they work… and even share some of the best free auto-warmers for your cold email campaigns

What are email warm-up tools?

Auto warmers are pieces of technology that automatically sends email on your behalf to controlled groups of recipients that will respond automatically. 

It tells spam filters that this “sender” has a good reputation, and therefore it helps increase your email deliverability rate. 

These tools also:

  • Generate positive engagement on your email account
  • Boost the chances of your email lading in your prospects inbox
  • Show service providers that you are a trustworthy sender. 

No one wants their well-written email to end up in the spam folder, firstly because spam emails are sometimes not even viewed. Or emails that are in spam are viewed as untrustworthy. If you want to avoid a bad sender reputation, then using an email warm-up tool will help you.

But besides all this, out of every 12,500,000 emails sent, spammers receive one reply. So you can see how this can affect your email outreach, especially if you are trying to find prospects for your business. 

Interestingly, spam emails have increased since 2020, especially regarding Covid-19, and studies show that nearly 85% of all emails are spam

This is why sales teams choose to use warm-up services for their campaigns, as it can help with deliverability issues

How do these tools work?

A bit of background information first…

You have an inbox with one of the email sender providers ( like Gmail, Microsoft, Yahoo, and Outlook) that you are a person that people like to interact with. 

Historically speaking, a few years ago, you had two types of people. Those who were sending legit emails, contacting their friends or co-workers, so engagement was high.

Secondly, you have spammers. A spammer sends lots of emails. People ignore the emails and flag them as spam. 

BUT there was a missing middle ground. Six years ago, for example, there were email automation tools such as Mailchimp and Active Campaign, but there wasn’t software for sales emails particularly.

When it comes to sending out sales emails, you can send them to prospects without spamming them to test the waters. For example, if you have a list of prospects, you could always send them a few good emails to see if they would be interested in your product/service.

Of course, though, your engagement will be way lower than if you’re contacting your friends or colleagues.

So there is a middle ground category, and if you are doing marketing emails badly,  no one will engage with you. Therefore you will be perceived as a spammer

This is where a “deliverability booster” can come in handy so that the email service provider is not going to block your email.

So, in short, email warm-up tools fill this gap between good and bad emails received by sending emails to a controlled group of accounts, who reply automatically to your emails. 

This then tells email service providers that you have a “good” sending reputation; therefore, when you start sending out emails to prospects, your mails won’t be sent to spam immediately. 

(Remember, even if you use automation tools such as Zapier — or any other API to send email — if your emails look legitimate and are not “spammy,” then the email service providers won’t be able to tell if you are sending the emails out yourself or not.


Today, sending an email using 3rd party tools is commonplace. So spam filters can not ignore this type of sending when factoring in a sender’s reputation.)

How long does the warm-up process take?

Let’s say you have a brand new account and would like to start with cold outreach campaigns. 

How long would it take to warm up your email? 

(A word of caution, the answer can change. When it comes to tech, the answer is never solid.

It’s fluid and can change with time. Google and Microsoft are not going to tell you that they are changing the game. Therefore once it happens, the software will need to be updated.)

Here is the current answer:

All tests show that it can take roughly two and three weeks to warm up email inboxes.

This depends, though, on the volume of emails that you intend to send.

A good auto-warmer should have a certain ratio between the number of emails you are sending that are totally cold and the number of emails you are sending through your auto-warmer. 

Remember, though, that this needs to happen slowly. You could send out 10 emails per day and then 10 emails through your auto warmer and then ramp it up with two additional emails per day. This gives you a 50/50 ratio.

But if you want to send 100 emails per day, you could have a ratio of 20/10, BUT it depends highly on how much engagement you get with your actual cold email activity

Remember, if you get good engagement rates, you only need a little bit of a boost. 

You can use a simple math formula for the right ratio.

For example, if you send 100 cold emails a day, you can then send 10-20 auto warmed mails. 

What’s written in the auto warmer emails?

Curious about what’s written in the emails? Is it just any old jumble of words? 

Some auto warmers use random questions in emails, such as “Do you have a lighter?”.

Others might list animal names, fruit, or vegetables.  

But this can seem quite random. You might worry that people monitoring emails at Google, for example, are keeping an eye out for things that don’t make sense, but we can’t be 100% sure of this., though, sends emails that include words or sentences from a cold email outreach book that they wrote. These words and sentences are constantly scrambled around. Therefore every email is different. 

This makes sense, as it seems like proper sentences and a legitimate email about sales and not just randomized words.

The funny thing about these sentences is that if you read it, it kind of makes sense but also doesn’t at the same time. 

The important thing is not exactly what’s written in the email, but more that it’s a mix of words and sentences so that each auto-warmer is unique. This can trick bots and, in some cases, even real people

Can email warm-up tools fix a bad email sending reputation?

What if your email domain has developed a bad sender reputation over time? Perhaps all your emails are getting flagged as spam or are sent straight to the spam folder

Can a mail-warmer get you off the blacklist? Or would you need to trash your domain name and set up a new domain?

The answer is yes, email warm-up tools could help you.


Well, there are two choices.

1. You could step back and just allow the auto warmer to do its thing. Increase engagement and deliverability. This takes about a month minimum to reset your lousy domain reputation. But this would mean that you would need to take a break from email, and not everyone has this luxury unless you’re on vacation. 

2. The second option is to create a new domain and warm up the email for 2-3 weeks. Once your domain reaches the 30-day mark, you will be off that “new email” blacklist.

PRO TIP: If you can, stay away from “.co,” as this is often viewed as spammy. Instead, use “.com,” “.io,” or “.net,”

Remember to keep using your auto warmer. Even if your open rates and deliverability are higher, keep using the auto warming tools. 

Are there any drawbacks to using email warm-up tools?

There are some drawbacks, in the sense that not all auto warmers are as good as others. 

Many new companies out there might have great marketing pitches, but their tools are not as great as others. (We will mention some of the best auto warmers out there shortly.)

Another drawback is that email warmers will not solve all your deliverability problems. You still need to focus on sending quality emails that are not spam. Quality over quantity will keep your domain reputation on solid ground.

What are some of the best cold email warm-up services?

1. Warmup Inbox

Warmup Inbox is a very simple and effective email warmup tool that works just the way it is supposed to.

It connects your inbox to a network of inboxes talking to each other and recreates the way a typical person would interact with an email address. This includes replying to the emails, marking them as important or, if needed, taking them out of s spam folder.

The whole process is automated and the “warmup” emails are filtered so it doesn’t affect the functionality of your inbox in any way.

The great thing about Warmup Inbox is that it uses a network of real inboxes. Also, the pricing is very straightforward and budget-friendly. They offer a 7-day free trial, then it’s $9/inbox/month. 

2. Auto Warmer

Quickmail offers a free auto warmer that will increase deliverability rates.

This is how QuickMails auto warmer works:  “Once you’ve linked your email account with the QuickMail Auto Warmer, your email address will automatically start sending and receiving emails to and from other real people using the Auto Warmer.

When an Auto Warmer email is sent from your address, it will be automatically opened and replied to, in the same way, a real email to a friend or coworker would be engaged with.

If your emails ever get caught in the filter, they’ll be automatically marked as ‘not spam’ and moved to the primary inbox to reduce the chances of it happening again.

With time, you’ll be showing ESPs that you’re a trustworthy sender that sends and receives real emails, making them less likely to flag you as a spammer when you launch your email campaigns.” 

The best part? It’s for free. 

3. Mailwarm

Mailwarm works in a similar way. Emails are also sent and replied to in order to give you a better sender reputation so that your outreach mails are not sent directly to spam. But it is quite a bit more expensive.

Have a look at the pricing below:

4. Lemwarm

Lemlist was the first to come to market with an email warmup solution (Lemwarm).

What is Lemwarm? It is a simple cold email warm-up tool that also connects to their email platform.

With Lemwarm, you can decide how many emails per day you want to send, and the tool will start automatically sending and replying to emails. 

There are various packages available, and you can choose to pay yearly or monthly.

To warm up or not to warm up?

An auto warmer isn’t really needed if you have a great sender reputation and excellent deliverability.

But if you would like to make sure that your emails land in your prospect’s inbox, a warm-up tool could really up your game. 

Remember, though, that even if you have a warm-up schedule as a marketer, you can just send the same template to thousands of prospects. (Because this will still give you a bad sender reputation.) 

Always focus on the quality of your email and not quantity when sending to your email list and if this is something that you are struggling with, give us a call.

Salesbread focuses on sending personalized emails to a targeted list of prospects who want what you’re selling. 

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