12 best email warm-up tools tested: Which should you choose to stay away from SPAM in 2025?
Have you spent hours crafting those perfect emails for them to finally land…but in SPAM? We know how frustrating that can be! Email service providers nowadays are stricter than ever about what they let through, and if your email accounts aren't warmed up properly, chances are, your emails will never see the light of day. Worse yet, when your deliverability is affected, so is your sender reputation and, ultimately, your entire success in cold outreach. But that's what you've got email warm-up tools for!
Think of them as personal trainers, but for your email. They exist to gradually build up your sender reputation, helping you avoid those dreaded spam filters so your emails land directly where they belong—in your recipients' primary inboxes.
Many companies have decided to develop their own email warm-up tools, resulting in your having quite a pick. The question is, how do you choose from the bunch?
There are several criteria that you should consider when deciding on the perfect email warm-up solution. We’ll go through each one in detail, but first, let’s explain:
- What email warm-up is,
- Why you should warm up your emails,
- The ins and outs of email warm-up tools.
As a cherry on top, we’ll walk you through 12 email warm-up tools we personally tested to help you find the perfect fit and boost your deliverability today!
| Email warm-up tool 🔥 | Best for 🥇 | Link 🔗 |
| InboxFlare | AI-powered, infinite email warm-up | Read more… |
| Lemwarm | Detailed deliverability insights | Read more… |
| Mailivery | Domain reputation tracking | Read more… |
| Warmbox | Simple self-setup | Read more… |
| Mailwarm | Flexibility in warm-up intensity | Read more… |
| Folderly | Keeping emails out of the Promotions folder | Read more… |
| Instantly | Automated cold emailing with the built-in warm-up | Read more… |
| Warm Up Your Email | Manual email warm-up | Read more… |
| MailReach | Real-time reputation tracking | Read more… |
| Smartlead | Email provider matching | Read more… |
| Mailflow | Blacklist tracking | Read more… |
| Allegrow | Integration with CRM and outreach platforms | Read more… |
What is email warm-up?
Email warm-up is the process of gradually increasing the number of emails sent from a new or low-activity account. This helps you build a positive reputation with email service providers (ESPs).
During the warm-up phase, you start by sending a small number of emails, either manually or automatically, through an email warm-up tool. These tools usually have a database of email addresses, often from other tool users. What they do is automatically exchange emails between these addresses and reply to them to simulate real conversations. Moreover, they typically organize warm-up emails into dedicated folders in your inbox to keep them from cluttering it.
This process helps make your email activity look natural to ESPs, showing them that your emails are valuable and wanted. As your engagement grows, you can safely scale your email outreach without risking your sender's reputation.
Benefits of email warm-up
In 2023, approximately 45.6% of all emails worldwide were marked as spam.
Want to make sure that doesn’t happen to yours? Start warming up your email accounts!
That said, here’s what you stand to gain from doing so!
1. Better deliverability
Warming up your account improves deliverability by building trust with email providers. When you start small and slowly increase your sending volume, providers recognize you as a reliable sender. This keeps your emails out of spam folders and makes sure they reach primary inboxes.
2. Lower bounce rate
When you warm up your account manually, you’ll probably take time to make sure you’re only sending emails to valid addresses likely to receive them. Email warm-up tools, however, already have a database of active and valid email addresses, helping you avoid sending to inactive ones. As a result, your bounce rate becomes lower. With fewer bounces over time, your account maintains a stronger standing reputation, ultimately supporting your long-term outreach success.
3. Improved sender reputation
Sender's reputation is like the credit score of email outreach. It’s the measure ESPs use to decide whether to trust your emails. Email warm-up builds this reputation steadily through positive interactions like opens and replies. A stronger reputation means your emails are more likely to reach their destination, helping you maximize your results.
What are email warm-up tools?
Email warm-up tools ''train'' your email account to handle large-scale outreach campaigns without triggering spam alarms. They automate the process of slowly ramping up your email-sending volume, which helps you establish a solid sender reputation with ESPs. By keeping your email activity consistent and boosting engagement, these tools improve deliverability, lower bounce rates, and set the stage for successful outreach.
How do email warm-up tools work?
Most email warm-up tools operate by sending emails from your account to a network of engaged contacts—often other users within the tool’s ecosystem. They also handle recipient interaction by opening emails, replying, and sometimes even marking them as ‘’Not spam.’’ This simulated engagement is what ESPs look for in trusted senders, making email warm-up tools a fast and reliable way to build credibility.
Common features of email warm-up tools include:
- Automated sending and replying: The tool sends a controlled number of emails each day, gradually scaling up. They also engage with these emails from the recipients’ side, mimicking real interactions that ESPs expect from reputable senders.
- Spam recovery: If any of your emails end up in spam, many tools can help pull them out to reinforce your sender's reputation.
- Customizable settings: Most tools offer flexibility, allowing you to adjust daily limits, warm-up duration, and engagement targets to align with your outreach goals.
Simply put, email warm-up tools make it easy to scale up safely. They handle the warm-up process automatically to allow you to run email campaigns that actually find their way to your audience.
Pros and cons of email warm-up tools
As you can see, email warm-up tools are pretty handy. But just like anything else, they are not perfect.
Let’s break down their pros and cons to get a full sense of what they offer and where they fall short.
Pros of email warm-up tools
1. Automated process
Email warm-up tools take the manual work out of the equation. They automate the sending, replying, and engagement needed to build up your reputation, which saves you time and ensures a consistent process.
2. Improved deliverability
By gradually increasing your sending volume and facilitating positive engagement between you and other tool users, email warm-up tools help you avoid spam filters and boost deliverability. As a result, your emails are more likely to land in your leads’ inboxes, which means more of them will actually see them.
3. Reputation building
Warm-up tools make it easier to build and maintain a good sender’s reputation. Many of these tools simulate human interactions, which ESPs recognize as positive signals. This reputation-building function is particularly important for new accounts or accounts that have experienced deliverability issues in the past.
4. Customizable settings
Most email warm-up tools offer settings you can adjust according to your requirements. This may include making adjustments to daily sending limits or setting the warm-up duration.
Cons of email warm-up tools
1. Subscription costs
Email warm-up tools can come at a hefty price. This cost may feel like a barrier to some, specifically when other expenses are also in play.
2. Potential for over-reliance
While great for warming up new accounts or improving deliverability, email warm-up tools don’t have the same quality. Moreover, relying solely on one without considering email content quality, frequency, or list hygiene could lead to issues down the road.
3. Lack of instant results
Building a reputation takes time, and even with automated assistance, it may take weeks for a new account to reach full-scale sending. So, if you’re looking for a quick fix, a warm-up tool might not be the immediate solution you need.
4. Varying success across providers
Some email service providers are more receptive to warm-up techniques than others. Depending on the ESPs you’re targeting, you may see different levels of success.
Best email warm-up tools to boost deliverability and stay away from spam
So, you know what email warm-up is all about. But now it's time to find the right tool for the job.
Lucky for you, we’ve curated a list of 12 email warm-up tools, all so we can help you improve deliverability, reduce bounce rates, and stay clear of those pesky spam filters.
1. InboxFlare - Best for AI-powered, infinite email warm-up
InboxFlare is an email warm-up tool that is only integrated with partnership tools like our Skylead. As a result, you get everything you need for outreach without paying extra!
Skylead has long been your ultimate LinkedIn automation and cold email software.
In fact, we were the 1st tool on the market to introduce Smart sequences—ground-breaking algorithms that let you take advantage of multichannel outreach to reach your leads wherever they are.
Smart sequences combine LinkedIn and email actions to form coherent outreach sequences that Skylead will follow to get in touch with your leads. This way, it makes sure you find the fastest path to your leads!
Now, thanks to our partnership with InboxFlare, we’ve taken Skylead to a whole new level!
We've become a real one-stop-shop solution that lets you:
- Harness the full power of LinkedIn automation and unlimited email outreach,
- Discover & double-verify leads' emails to reduce bounce rates and protect your domain,
- Hyper-personalize GIFs and images to increase your response rate to over 76%,
...but also warm up infinite email accounts to keep your emails away from spam—forever!
That's right! You get all of this at one cost!
All Skylead users can create InboxFlare accounts to start warming up their emails in 30+ languages.
Once you’ve created the account, just add your email and let InboxFlare handle the rest. It's compatible with all major email providers, including Gmail, Outlook, and Zoho, and also supports custom SMTP.
InboxFlare’s AI crafts a warm-up strategy customized to your domain’s unique needs, improving your sender reputation on autopilot.
But it doesn’t send just any generic warm-up emails—you can choose specific topics, and it will generate and send customized messages on your behalf, making the warm-up process even more authentic.
In addition to building reputation, InboxFlare continuously monitors your email health by checking blacklists, domain configurations, and inbox settings.
Plus, you can run deliverability tests to assess whether your mailbox server is blacklisted, see where your emails land in different inbox providers, and adjust warm-up accordingly.
Pricing
InboxFlare comes at no extra cost! With a Skylead subscription, you can warm up an infinite number of emails and unlock every other feature Skylead offers—all for just $100 a month.
That means full power to boost your deliverability, automate email and LinkedIn outreach, and manage leads in one package.
2. Lemwarm by Lemlist - Best for detailed deliverability insights
Lemwarm is an email warm-up tool developed by Lemlist. But since it’s an add-on rather than integrated into the platform, it’s available for standalone usage.
It works by sending automated emails to a network of over 20,000 users, gradually boosting your deliverability.
The tool also offers alerts on your deliverability score, spam risk detection based on your email content, and daily insights with expert tips to optimize performance.
Moreover, detailed deliverability reports help you stay on track and keep your emails landing in the right place.
However, the pricing structure is based on the number of emails you warm up, meaning costs can quickly add up.
Not to mention, while our testing ran smoothly, one reviewer, Vinayak G., noted:
‘’All our warm-up emails were going to the spam and categories section, which was really frustrating.’’
So, while Lemwarm proved effective to us, specific cases suggest it’s not ideal.
Pricing
Lemwarm is free for Lemlist users.
If you’d like to use it alone, you can, but expect to pay the following amount:
| Essential Plan | $29/mo per email account |
| Smart Plan | $49/mo per email account |
3. Mailivery - Best for domain reputation tracking
Mailivery is an AI-driven email warm-up tool designed to boost deliverability by interacting with real emails behind the scenes.
It removes emails from spam, generates positive replies, like Lemwarm, and works with a network of over 20,000 real users to simulate authentic engagement.
Its intuitive dashboard provides real-time insights into spam placement and detailed analytics to track your domain reputation. What’s more, you can check if you're blacklisted and get personalized recommendations for improvement.
While Mailivery offers full customization of warm-up volume and timing, which we liked, some users report there’s a bit of a learning curve to it.
Additionally, the tool limits the number of warm-up emails sent daily despite allowing you to warm up unlimited mailboxes.
Pricing
| Free *1 email account / up to 10 interactions a day | |
| Starters | $29/mo *Unlimited email accounts / up to 100 interactions a day |
| Professional | $79/mo *Unlimited email accounts / up to 600 interactions a day |
| Business | $199/mo *Unlimited email accounts / up to 2,000 interactions a day |
4. Warmbox - Best for simple self-setup
Warmbox is one of the easiest email warm-up tools to use and is great for those who want a simple, self-setup experience.
The software automates the whole email-warm-up process using inboxes from real users and doesn’t interfere with your email routine.
Beyond improving deliverability, Warmbox also calculates your Reputation Score, compares it against a community benchmark, and suggests ways to improve. It even sends you alerts if your score drops below a certain percentage, so you can pause campaigns before things get worse.
However, it can get pricey, especially since you’re charged per inbox, and there’s no free trial available.
Pricing
| Basic | $19/mo per inbox *Up to 75 warm-up messages a day |
| Pro | $59/mo per inbox *Up to 250 warm-up messages a day |
| Max | $99/mo per inbox *Up to 1,000 warm-up messages a day |
5. Mailwarm - Best for flexibility in warm-up intensity
Mailwarm helps raise your sender reputation by interacting with your emails daily.
It automatically sends dozens of emails to over 1,000 Mailwarm accounts, where they get opened, marked as important, replied to, and pulled out of spam.
You can track everything through a dashboard that gives you insights into your email activity. You also have the flexibility to adjust Mailwarm’s intensity or pause the warm-up process if and when necessary.
Nevertheless, the major limitation we found is that even with the highest subscription plan, you’re capped at warming up a maximum of 10 inboxes. And considering its hefty price, you may be better off choosing a different email warm-up software.
Pricing
| Starter | $79/mo per user with 1 email account |
| Growth | $189/mo per user with up to 3 email accounts |
| Scale | $549/mo per user with up to 10 email accounts |
6. Folderly by Belkins - Best for keeping emails out of the Promotions folder
Folderly is developed by Belkins, a company known for its B2B lead generation and outreach services.
Its main promise is to keep your emails out of spam and promotions folders with an impressive 99% inbox placement rate. It offers insights on why emails end up in spam, helps you optimize templates, checks your DNS records, and integrates with the most popular ESPs like Gmail and Outlook.
We haven't experienced major issues while testing Folderly, but multiple users have complained about it doing more harm than good.
And after reading this review left by Oguzhan U., in particular, we are seriously starting to question the tool’s reliability:
‘’Folderly sent 42,000 undelivered emails in 2 days (Saturday and Sunday) using 8 email addresses in our domain. Our team didn't realize the issue until Monday. Our email domain reputation is completely destroyed. That is completely the opposite of why we wanted to use Folderly.’’
Pricing
Folderly doesn’t have pricing plans, per se.
Instead, their rates depend on the number of mailboxes you’re warming up and are structured like this:
| 1-9 mailboxes | $120/mo per mailbox |
| 10-24 mailboxes | $90/mo per mailbox |
| 25-99 mailboxes | $70/mo per mailbox |
| 100+ mailboxes | Custom / Contact sales |
7. Instantly - Best for automated cold emailing with the built-in warm-up
Instantly isn't a standard email warm-up tool but a cold email software with built-in warm-up functionality that can be activated with a click.
The software allows you to monitor your deliverability score, showing exactly how many emails land in the inbox or spam. You can also emulate human-like reading by enabling the read emulation feature, which scrolls through emails to simulate authentic interaction.
The tool sends a random number of warm-up emails daily, and you can choose specific open and response rates.
Moreover, with a pool of over 550,000 real email accounts for warm-up, Instantly.ai's coverage is vast.
The price is reasonable, considering that, starting at $37, you can warm up unlimited emails.
Nonetheless, some users have reported that its warm-up can blacklist your domain with certain ESPs, so exercise caution if you decide to use it.
Pricing
Instantly doesn’t have a dedicated email warm-up plan.
Nonetheless, email warm-up is included in their following Sending & Warmup plans, along with email outreach.
| Growth | $37/mo per seat *Unlimited warm-up / 5,000-email monthly send limit |
| Hypergrowth | $97/mo per seat *Unlimited warm-up / 100,000-email monthly send limit |
| Light Speed | $358/mo per seat *Unlimited warm-up / 500,000-email monthly send limit |
8. Warm Up Your Email by Mailshake - Best for manual email warm-up
Mailshake, a popular cold email software, acquired the email warm-up tool ‘’Warm Up Your Email’’ in 2024 to ensure its customers' emails hit the inbox, not the spam folder.
The team at Warm Up Your Email manually interacts with your emails by opening them, replying, and pulling them out of spam. This interaction helps signal ESPs that you’re a trusted sender.
All you have to do is connect your email account and set your daily send volume while they handle the rest. You’ll get insights on how many of your emails land in spam and track your progress with a 10-day spam pattern report that shows your account’s improvement over time.
The downside? The process isn’t fully automated—it’s done manually by the Warm Up Your Email team. This can feel a bit counterproductive if you’re looking for full automation.
Additionally, their top plan caps the number of email accounts you can warm up at 8.
Not to mention, replies are sent as separate messages, not within the same thread, which might limit the natural conversation flow.
Pricing
Mailshake users can use Warm Up Your Email free of charge.
As for those who’d like to use it separately, the available plans are as follows:
| Sole Sender | $29/mo per user *1 email account / up to 50 interactions a day |
| Pro Sender | $49/mo per user *3 email accounts / up to 50 interactions a day |
| Agency Sender | $99/mo per user *8 emails accounts / up to 100 interactions a day |
9. MailReach - Best for real-time reputation tracking
MailReach is an email warm-up tool designed to enhance your email deliverability, helping you hit more inboxes and land more deals.
It automatically repairs, improves, and maintains your sender reputation by facilitating genuine, positive interactions with a network of high-reputation accounts.
Its main feature is consistent spam checking, which allows you to track inbox placement and measure deliverability performance. You can run these tests manually or automate them based on your preferred frequency.
MailReach comes with a Smart AI warming algorithm that makes sure your account is properly warmed up before hitting full-scale outreach. At the same time, the Reputation Tracking Dashboard gives you real-time insights into your email performance, allowing you to fine-tune your campaigns as needed.
MailReach works with any email service provider that supports SMTP. However, the setup process can be tricky, especially when connecting emails for the first time.
Downsides-wise, since pricing is inbox-based and spam checker credits aren’t included in the base cost, you’ll need to account for those extras when budgeting.
Pricing
MailReach prices are based on the number of mailboxes you’re warming up, starting at $25 per mailbox.
Spam credits are sold separately, starting at $28 for 100, though you get 20 free credits to start you off.
10. Smartlead - Best for email provider matching
Smartlead is another tool that bundles email warm-up into its larger cold outreach infrastructure.
Its AI-powered warm-up emulates human conversations, allowing emails to appear natural and avoid automation detection. In addition to authentic AI conversations, the system delivers a gradual ramp-up for safe email sending.
One feature we really liked is how Smartlead automatically matches your email provider with that of your recipient. So, for instance, if you have both Gmail and Outlook accounts, and your recipient is using Gmail, Smartlead will use your Gmail account for optimal deliverability.
One downside, however, is the lack of customization—you can’t choose the topics or content for the warm-up messages. For this reason, and the fact that other warm-up tools offer more functionalities, you may be better off opting for one of the Smartlead alternatives.
Pricing
Much like Skylead and Instantly, Smartlead doesn’t have a sole email warm-up plan.
Instead, this functionality is included in their standard plans, which also give you access to email outreach.
| Basic | $39/mo per user *Unlimited email warm-up / Up to 2,000 active leads |
| Pro | $94/mo per user *Unlimited email warm-up / Up to 30,000 active leads |
| Custom | $174/mo per user *Unlimited email warm-up / Up to 12M active leads |
11. Mailflow by QuickMail - Best for blacklist tracking
Mailflow is QuickMail's email warm-up tool, primarily aimed at its users. Nevertheless, it can also be used separately.
The tool is designed to improve your email deliverability with features like a real-time auto-warmer score for each inbox, SPF and DKIM monitoring, and blacklist tracking across nearly 100 lists. The latter makes it easy to act quickly if any blacklist flags your domain.
Unfortunately, its analytics are somewhat limited for our taste. In addition, the support team is only accessible via email, which can delay issue resolution.
Pricing
The tool is free for all QuickMail users.
Nevertheless, those who’d like to use it separately can expect to pay the following amounts:
| Free Pool *Up to 100 email accounts / maximum 5 warm-up emails a day | |
| Silver Pool | $49/mo per user *Up to 100 email accounts / maximum 30 warm-up emails a day |
| Gold Pool | $99/mo per user *Up to 100 email accounts / maximum 50 warm-up emails a day |
12. Allegrow - Best for integration with CRM and outreach platforms
Allegrow is an email warm-up tool focused on delivering in-depth insights to help optimize your deliverability.
It offers unique features like Spam Rate Analysis, allowing you to see exactly how much of your email traffic ends up in spam. Also, there’s the Safety Net™, which automatically stops emails that could damage your sender's reputation.
With continuous DKIM, SPF, and DMARC testing, like InboxFlare in Skylead has, you’re also covered in authentication. At the same time, the Deliverability Leaderboard ranks users by spam rate to prevent one bad sender from affecting the whole team.
Another plus is that Allegrow natively integrates with popular CRM and sales outreach tools like Outreach.io and SalesLoft.
Not everything is ideal about Allegrow, though. The lack of pricing transparency is a con in our eyes. Moreover, the customization of warm-up messages is rather limited.
Pricing
Allegrow doesn’t share its pricing details publicly, so it’s likely they adjust prices based on the number of connected mailboxes.
However, sources suggest their plans start at $300 for 10 inboxes, which is, consequently, also the minimum you can connect.
How to choose an email warm-up tool
You’ve seen the top email warm-up tools—now let’s show you how to pick the best one for your workflow.
1. Look for features you need
Not all email warm-up tools are created equal, meaning they come with different features. With that in mind, start by identifying the ones that matter most to you.
Do you need automated sending and replying?
Customizable warm-up settings?
Or perhaps spam recovery features?
Either way, the tool you choose should have the functionality you need. Otherwise, what’s the point of paying for it?
2. Verify ESP compatibility
Before you invest in a tool, check that it’s compatible with your ESP. Some tools are specifically suited for Gmail, while others are optimized to work better with Outlook, Zoho, or more specialized ESPs. This step saves you from potential headaches down the line.
3. Assess ease-of-use and setup
Your ideal warm-up tool shouldn’t have a steep learning curve. Instead, it should be simple to set up and easy to navigate.
That said, look for intuitive dashboards, straightforward settings, and clear instructions. The less time you spend figuring out the tool, the sooner you’ll start seeing results.
4. Confirm support for multiple accounts and team usage
Running campaigns across multiple accounts and teams? You’ll want a tool that can handle it. So, make sure the tool supports multi-account use and includes team collaboration features. That way, you can streamline your efforts and keep everything organized.
5. Gauge the quality of customer support
Customer support can make or break your experience with any tool. After all, if things go sideways, you’ll need reliable help.
But how do you know the support quality if you haven’t used the tool yet? Check out reviews from real users. Their feedback usually reveals how responsive and helpful the support team is and whether they’re truly invested in resolving issues.
Ideally, the support team should be reachable 24/7 through multiple channels—live chat, email, phone, you name it.
6. Evaluate cost vs. feature ratio
Finally, consider whether the cost is appropriate for what you’re getting. Some tools are pricey but lack crucial features. Meanwhile, others offer everything you need at a reasonable rate. Compare pricing plans and weigh the cost against features to make sure you’re getting the best quality you can afford.
Frequently asked questions (FAQs)
Is email warmup necessary?
Yes, if you want your emails to reach inboxes instead of spam folders. Skipping this step can result in poor deliverability and a damaged reputation. Both of these can seriously hurt your outreach.
How can I warm up my email?
You have 2 options: manually or with an email warm-up tool.
To warm up manually, start by sending a small number of emails each day to trusted contacts—people who will open, reply, and engage with your messages. Gradually increase the volume over several weeks, allowing email providers time to recognize your account as trustworthy.
For a faster and more efficient approach, consider using an email warm-up tool. These tools automate the process by sending emails to a network of engaged users who interact with your messages, helping to quickly build your sender reputation and improve deliverability with minimal effort.
What is the best email warm-up tool?
One person's best may be another person's worst. So, the best email warm-up tool for you is the one that has the features you need, all while fitting within your budget.
Did Google ban email warmup?
Google didn’t ban email warm-up outright. However, they have restricted the use of third-party tools that access the Gmail API, which is often used for email warm-up. However, this move is about enforcing their policies against unauthorized API access, not banning the concept of warm-up itself.
That said, this doesn’t mean you can’t use email warm-up tools altogether. Many tools offer warm-up services that comply with Google’s policies by avoiding direct API access or by using methods that align with Gmail’s guidelines. So, if you’re using Gmail, just make sure you choose a tool that follows these regulations to avoid any issues.
Email warm-up tools: Final comparison
Your search for effective email warm-up tools ends here!
By now, you should understand just why you should warm up your emails.
And sure, there are plenty of email warm-up tools out there. But here’s the bottom line: your emails deserve to be seen. So, why mess around testing each tool when there’s already one that does it all—Skylead?
Skylead is a one-stop-shop tool that can help you warm up an infinite number of emails, discover and verify your leads' emails, and automate your LinkedIn and email outreach—all at a single price!
Sounds too good to be true?
Take it for a spin with our 7-day free trial to see the results yourself and start getting your emails exactly where they belong: in front of your audience!
