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5 Best AI Email Warmup Tools to Boost Deliverability in 2026
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5 min read
I’ve seen this pattern too many times: you set up a new domain, start sending, and for a few days, everything looks fine.
Then replies drop, open rates fall, and emails start landing in spam.
I recently saw a discussion where someone explained it clearly.
The domains they didn’t warm up were the first to lose deliverability, no history, no trust.
That’s what most people miss.
Cold email isn’t just about sending volume.
It’s about how your activity looks over time:
- Are emails getting opened?
- Are there real replies?
- Does the behavior look consistent?
If not, things break early.
The problem is, most email warmup tools still rely on random activity that doesn’t reflect real inbox behavior.
That’s why a lot of teams have started looking at AI-based warmup setups.
Instead of just sending emails, they try to:
- Simulate real conversations
- Generate replies and engagement
- Maintain more natural sending patterns
In this guide, I’ll break down 5 AI email warmup tools to help you choose what fits your setup.
Key Takeaways - 5 Best AI Email Warmup Tools to Boost Deliverability
- Warmforge → Best when you’re scaling outbound and need both AI warmup + deliverability visibility (placement, readiness, health) so you know when to start sending
- Warmy.io → Useful when your main problem is emails landing in spam and you want to track placement, reputation, and fix issues
- TrulyInbox → Fits when you’re adding more inboxes and want to keep costs low with volume-based pricing
- Warmbox → Good if you just want a simple, automated warmup running without managing much
- Lemwarm → Works when you want continuous monitoring, alerts, and long-term deliverability stability
How We Selected These AI Email Warmup Tools
We didn’t just compare features.
Each tool was evaluated based on how its AI-driven warmup actually behaves in a real cold email setup.
- How the AI generates warmup activity (random vs conversation-like patterns)
- How engagement is created (AI replies, opens, interaction quality)
- Ability to mimic natural sending behavior over time
- Control over warmup settings and patterns
- Ease of setup and day-to-day usage
- Ability to scale across multiple inboxes or domains
This helps you understand not just which tool has AI, but how that AI actually impacts your deliverability.
Quick Comparison: AI Email Warmup Tools (2026)
1. Warmforge
Warmforge is an email warmup and deliverability tool that uses AI-driven activity to help you build sender reputation while also monitoring your mailbox health in one place.
Instead of just sending basic warmup emails, it uses AI to generate unique emails and simulate real activity inside your mailbox, including sending, opening, and replying.
This makes the behavior look more like actual human interaction.
At the same time, it also works as a deliverability layer, where you can:
- Track mailbox health (DNS, MX records, blacklist status)
- Run placement tests to see where your emails land (inbox vs spam)
- Monitor overall performance across different ESPs
It also includes a Heat Score™, which shows how ready your mailbox is for sending:
- A score above 85 means your mailbox is ready to start outreach
So instead of just warming up inboxes, Warmforge combines AI-driven activity with deliverability tracking to help you manage how your emails behave as you scale.
From what I see, the useful part here is that you’re not just warming up blindly.
You can actually see how your mailboxes are performing and decide when to start sending instead of guessing.
Pricing
Warmforge uses a mailbox slot-based pricing model, so your cost depends on how many inboxes you want to warm up.
- Starts at $9 per mailbox/month (billed annually)
- Includes:
- Automated warmup
- 1 free placement test per month
- Health checks (DNS, MX, blacklist)
- Automated warmup
As you add more inboxes, the total cost increases linearly.
For example:
- 10 mailboxes → ~$90/month
- 20 mailboxes → ~$180/month
Placement test add-ons:
- Pro Plan → ~100 tests/month, up to 50 mailboxes/test (~$32–$39/month)
- Growth Plan → Unlimited tests, up to 250 mailboxes/test (~$140–$169/month)
So the pricing is directly tied to how large your outbound setup is.
The good part here is the clarity; you always know what you’re paying based on the number of inboxes.
At the same time, this also means your cost scales directly with your setup.
So the more you expand your outreach, the more you need to account for warmup as a fixed cost in your system.
Pros
- Improves inbox placement by building sender reputation steadily over time
- Creates more natural email activity, helping build trust with inbox providers
- Helps identify deliverability issues early, before campaigns start dropping
- Placement tests show actual inbox vs spam performance before sending campaigns
Cons
- Needs to run continuously; stopping can hurt your sending consistency
Who Should Use Warmforge?
Use Warmforge if:
- Running multiple inboxes and need a consistent warmup across all
- Want warmup and deliverability tracking in one place
- Prefer knowing when a mailbox is ready (using Heat Score)
- Need to check the inbox vs spam before launching campaigns
- Fine with keeping the warm-up running continuously
From what I see, this works best when the goal is to keep deliverability stable while scaling outreach without constantly checking what’s going wrong.
Skip Warmforge if:
- Only need basic warmup without extra tracking
- Running a small setup and want to keep costs low
- Prefer manual control over automation
- Don’t need placement testing or deeper visibility
From a practical side, this can feel like more than you need if you’re just testing cold email with a small setup.
2. Warmy.io
Warmy.io is an email warmup and deliverability tool that uses AI-driven automation to help improve inbox placement while giving you visibility into how your emails perform.
Instead of just running a warmup in the background, it focuses on both sides, building sender reputation and showing you what’s actually happening with your emails.
It uses AI along with tools like Google Postmaster to:
- Improve deliverability and domain reputation
- Track where emails land (inbox, spam, promotions)
- Help optimize settings to avoid spam filters
At the same time, it gives you a dashboard where you can:
- Monitor deliverability performance
- Check the domain and DNS health
- Identify and fix issues affecting inbox placement
So it’s not just about warming up, it’s also about understanding and improving how your emails behave.
What I like here is that it doesn’t just run a warmup in the background; it actually shows you where things are breaking.
Pricing
Warmy doesn’t show fixed pricing publicly.
- Uses a volume-based pricing model
- Plans differ based on:
- B2B vs B2C sending
- Usage and scale
- B2B vs B2C sending
- Offers a 7-day free trial (no credit card required)
- Requires booking a demo or selecting a plan to see exact pricing
What I don’t like here is the lack of clarity.
You don’t get a quick idea of cost like per mailbox pricing, so it’s harder to estimate how much it will cost as you scale.
Pros
- Helps improve inbox placement by optimizing deliverability, not just warming up
- Gives clear visibility into where emails land (inbox, spam, promotions) and reputation
- Helps identify and fix deliverability issues early
- Uses Google Postmaster data to track domain reputation
- Supports both B2B and B2C email setups
Cons
- Pricing is not transparent upfront and depends on usage
- Requires understanding of deliverability data to fully use its features
Who Should Use Warmy.io?
Use Warmy.io if:
- You want more visibility into deliverability, not just warmup
- You care about tracking inbox placement and domain reputation
- You want to actively improve and optimize your email performance
- You’re running either B2B or B2C outreach setups
From what I see, this works better when you want to understand and improve deliverability continuously, not just set up warmup and leave it running.
Skip Warmy.io if:
- You prefer simple, fixed pricing without needing to calculate usage
- You only need basic warmup without deeper insights
- You don’t want to deal with deliverability data or optimization
From a practical side, this can feel a bit heavy if you just want a simple “set it and forget it” warm-up setup.
3. TrulyInbox
TrulyInbox is an AI-powered email warmup tool that focuses on generating warmup activity that closely matches your real outreach.
Instead of sending generic warmup emails, it lets you define your context, like industry and topics, and then generates emails that look similar to what you would actually send.
It supports different warmup strategies like progressive, random, and flat, while using AI to create emails with human-like timing and replies.
Along with warmup, it also gives you visibility into your setup through a deliverability score, an outreach readiness indicator, and performance tracking across different email providers.
It runs on a large network of real inboxes, which helps create more varied and realistic interactions during warmup.
So instead of just increasing activity, it focuses on making that activity look closer to real conversations.
What I like here is that the warmup doesn’t feel generic; it actually aligns with how your real emails would look.
Pricing
TrulyInbox keeps pricing straightforward and not tied to the number of accounts.
- Free plan → 1 account, 10 warmup emails/day
Paid plans:
- Starter → ~$22/month (200 warmup emails/day)
- Growth → ~$59/month (1,000 warmup emails/day)
- Scale → ~$142/month (3,000 warmup emails/day)
- Unlimited inbox connections across plans
- 7-day free trial available
You can connect multiple inboxes, and the total warmup volume gets distributed across them.
What I like here is that it stays cost-efficient as you scale inboxes, since you’re not paying per account.
At the same time, your warmup speed depends on your plan, so if you add more inboxes, each one gets fewer warmup emails unless you upgrade.
Pros
- Warmup emails match your actual outreach, making the activity feel more realistic
- Clear deliverability score and readiness indicator
- Works across multiple inboxes without extra cost per account
- Flexible warmup strategies based on your setup
- Simple setup with quick onboarding
Cons
- Daily warmup limits can slow things down as you add more inboxes
- Warmup volume gets split across inboxes, reducing effectiveness per account
Who Should Use TrulyInbox?
Use TrulyInbox if:
- You want a warm-up that matches your actual outreach style
- Running multiple inboxes, but don’t want per-mailbox pricing
- Prefer clear signals, like a deliverability score, before sending
- Want control over warmup strategy without making it complex
From what I see, this works best when you want something simple but still aligned with how your real campaigns look.
Skip TrulyInbox if:
- You need unlimited volume without plan limits
- You prefer fixed pricing based on inboxes instead of usage
- You don’t need control over warmup strategy or customization
From a practical side, limits can start to matter once your volume increases.
4. Warmbox
Warmbox is an email warm-up tool that focuses on automatically generating realistic email activity to improve your sender reputation.
Once you connect your inbox, it starts sending and interacting with emails on your behalf, opening, replying, marking emails, and even pulling messages out of spam.
So your inbox activity looks more natural over time.
It uses a mix of GPT-4 and hybrid systems to generate emails and interactions, and runs this across a large private network of inboxes to create consistent engagement.
You can also choose how the warmup behaves, whether gradual, random, or more controlled, depending on your setup.
Along with that, it gives basic monitoring like spam score tracking, blacklist checks, and overall deliverability reporting.
So the focus here is simple: run a warmup automatically and keep your inbox active without manual effort.
What I like here is how hands-off it feels once it’s set up; you don’t really need to manage much day-to-day.
Pricing
Warmbox uses a tier-based pricing model, where both inbox count and daily warmup volume are bundled into each plan.
- Solo → $15/month (1 inbox, 50 emails/day)
- Start-up → $69/month (3 inboxes, 250 emails/day)
- Growth → $139/month (6 inboxes, 500 emails/day)
- Includes:
- Automated warmup
- Inbox interactions (reply, open, remove from spam)
- Spam score monitoring
- DNS & blacklist checks
- Automated warmup
Custom plans are available for larger setups.
You’re not just paying per inbox or per usage, you’re choosing a tier that locks:
- number of inboxes
- and warmup volume
together.
That makes it simple to understand, but less flexible.
But if you’re somewhere in between, like needing slightly more inboxes or volume, you’re forced to jump to the next tier, even if you don’t fully use it.
So pricing here is predictable, but not very granular when you start scaling.
Pros
- Creates realistic interactions (opens, replies, spam removal) to build reputation
- Fully automated once set up, with minimal manual work
- Supports different warmup strategies based on your setup
- Works across multiple email providers
- Includes basic monitoring like spam score and blacklist checks
Cons
- Basic visibility compared to tools focused on deliverability insights
- Not ideal if you want deeper control over warmup behavior
Who Should Use Warmbox?
Use Warmbox if:
- You want a simple setup that runs automatically after connecting inboxes
- Prefer not managing warmup manually day-to-day
- Running a small to mid-size setup with limited inboxes
- Want realistic interactions without setting up complex workflows
What stands out to me is how easy it is to get started and let it run without much involvement.
Skip Warmbox if:
- You need flexible scaling without moving across pricing tiers
- Managing a large number of inboxes
- Want deeper deliverability insights beyond basic monitoring
If your setup grows quickly, the plan limits can start to feel restrictive.
5. Lemwarm
Lemwarm is an email warmup and deliverability tool that focuses on gradually building sender reputation and continuously monitoring your email performance.
It warms up your inbox by sending automated emails through a large network of domains, while also generating replies to make the activity look more natural.
Along with warmup, it also keeps track of your setup, checking things like technical configuration, sending behavior, and content signals that might affect deliverability.
It doesn’t just stop after warm-up.
It continues to:
- Monitor your deliverability score
- Alert you about potential spam risks
- Give insights on how to improve performance
So the focus here is not just warming up once, but maintaining deliverability over time.
What I like here is that it keeps running even after warmup, so you’re not just setting things up and leaving them.
Pricing
Lemwarm uses a per-email pricing model, where you pay for each email account you warm up.
- Essential Plan → ~$24–$29 per email/month
- Smart Plan → ~$40–$49 per email/month
- Includes:
- Automated warmup
- Deliverability reports
- Technical setup checks
- Access to warmup network
- Automated warmup
Higher plan adds:
- Personalized warmup emails
- Custom alerts and tips
- Industry-based warmup network
So as you add more inboxes, your cost increases per mailbox, not based on volume or tiers.
What I don’t like here is how quickly costs can add up if you’re running multiple inboxes.
Pros
- Helps maintain deliverability continuously, not just during warmup
- Identifies risks in setup, sending behavior, and content
- Provides ongoing insights to improve performance
- Uses a large and diverse warmup network
- Sends personalized warmup emails for more natural activity
Cons
- Becomes expensive as you add more inboxes
- Needs to stay running, stopping warmup can hurt deliverability
- Less flexibility in controlling warmup behavior
- Takes time to see results, not ideal for quick setup
Who Should Use Lemwarm?
Use Lemwarm if:
- You want ongoing deliverability monitoring, not just initial warmup
- You prefer getting alerts and insights on what’s affecting your emails
- Running campaigns where consistency over time matters
- You’re already using Lemlist or similar workflows
From what I see, this works best when you treat deliverability as something you manage continuously, not just fix once.
Skip Lemwarm if:
- You want a low-cost setup for multiple inboxes
- You prefer volume-based or flexible pricing
- You only need a basic warm-up without ongoing monitoring
From a practical side, this can get expensive quickly if you scale across many inboxes.
Personalized Outbound Strategy
Get The Right Outbound Strategy In Minutes
Enter your email to get a custom plan & stack recommendation for your business
It's being carefully crafted by AI
Please check your mailbox in 5 minutes
Which AI Email Warmup Tool Should You Choose?
It really depends on what you need right now: warmup, visibility, cost, or control.
- Warmforge makes the most sense when you’re scaling outbound and need both warmup and deliverability tracking together, so you know when to start sending and what’s happening across inboxes
- Warmy.io fits better if your main focus is understanding where your emails land and actively improving deliverability using insights
- TrulyInbox works well when you’re trying to manage multiple inboxes at a lower cost and don’t want pricing tied to each account
- Warmbox is useful if you just want a simple setup that runs warmup automatically without much involvement
- Lemwarm makes more sense when your focus is on ongoing monitoring and keeping deliverability stable over time
If you’re planning to scale seriously, Warmforge stands out because it doesn’t just warm up inboxes.
It also helps you track, manage, and decide when your setup is actually ready to send.
Try Warmforge with 1 free warming slot and 1 free placement test, and check if your emails are landing in the inbox.