Have you ever spent hours perfecting an email campaign, only to discover your messages landed straight in the spam folder? It’s frustrating, disheartening, and, unfortunately, all too common.
Email providers today are more vigilant than ever. Without proper preparation, your emails might never reach your prospects’ inboxes. Poor deliverability not only wastes your efforts but also damages your sender’s reputation.
That’s where email warm-up tools come in.
Think of them as personal trainers for your inbox. These tools gradually build your email account’s reputation by simulating real, organic interactions, so your messages end up in the primary inbox, not the junk folder.
With the rise of cold outreach, many companies have built their warmup tools, offering different features, networks, and strategies. But with so many choices, how do you find the one that’s right for you?
In this guide, we’ll break down everything you need to know—from how warmup tools work, to what to look for when choosing one, and the best-in-class email warmup tools available today.
Let’s dive in.
Why Email Warmup Is Crucial for Cold Outreach Success
Before sending any cold email, you need to warm up your email account. This warmup process gradually increases your email volume and builds a positive reputation with email and internet service providers. Without it, your cold email campaign is likely to end up in the spam folder, wasting your time and damaging your email domain.
Email warm up simulates real human interaction by using automated email sending and receiving patterns, which help your messages land in the inbox rather than the junk folder. A good warmup tool can make this process seamless and effective.
How Email Warm-up Tools Work Behind the Scenes in an Inbox
Most warmup tools operate using a network of real or simulated email accounts that interact with each other. These warmed-up emails are sent, opened, replied to, and moved out of spam folders — all of which help improve your sender’s reputation.
Some advanced tools use GPT-4-generated warmup emails that are more context-aware, increasing engagement and helping to improve email deliverability. Those tools also monitor your email engagement metrics like open rate and reply rate to fine-tune the warmup process.
Top Benefits of Using an Email Warmup Tool in 2025
- Improved Inbox Placement: Tools help your emails land in the primary mail section.
- Spam Avoidance: They avoid spam filters by simulating legitimate activity.
- Boosted Sender Reputation: With a solid email sender history, you’ll gain credibility.
- Time-Saving Automation: Completely automated systems do the heavy lifting for you
- Email Metrics: Higher email view rates, better engagement, and improved deliverability.
- Improved Inbox Placement: Tools help your emails land in the primary mail section.
What Happens If You Don’t Warm Up Your Email?
If you skip the warmup inbox stage, you risk landing in junk, damaging your sender reputation, and presumably being blacklisted by email service providers. Without a proper warmup, your emails look suspicious to internet service providers and junk filters.
This can lead to emails never reaching prospects or being flagged immediately. Even a new domain or email address must be handled carefully — you need to warm up your email before launching large campaigns.
Email Deliverability and the Warmup Connection
Your email deliverability depends heavily on your ability to maintain a good email reputation. Warming up an email account is a key part of that. As the email volume gradually increases, providers recognize your domain as trustworthy.
Warmup also ensures your emails pass basic email authentication protocols like SPF, DKIM, and DMARC, further helping you land in the right place and not in the junk folder.
Best Email Warmup Tools in 2025 (With Features and Pricing)
1. Warmbox.ai
Warmbox is one of the most advanced standalone platforms on the market. It connects your email to a private network of over 10,000 real email folders and mimics authentic email engagement—sending, opening, replying, marking as important, and even removing your emails from junk folders. It’s ideal for individuals, teams, and agencies wanting to protect their sender reputation with minimal manual effort.
Key Features:
- AI-driven engagement and replies to simulate human conversation
- Custom warmup strategies (slow, aggressive, or balanced)
- Domain reputation scoring and email folder placement reports
- Junk score alerts and deliverability insights
Pricing:
- Starter: $15/month (basic warmup features)
- Pro: $69/month (advanced engagement)
- Premium: $139/month (for agencies and multiple mailboxes)
2. Mailwarm
Mailwarm focuses solely on warming up your email account by having your email folder interact with a network of real, trusted accounts. It’s simple, effective, and made for sales professionals and outbound teams who want to improve their sender score and inbox placement without needing extra bells and whistles.
Key Features:
- Sends 50 to 200 warmup emails per day
- Fully automated – no manual input needed
- Real human-like email threads and responses
- Dashboard to track daily activity and deliverability metrics
Pricing:
- 50 warmup emails/day: $69/month
- 200 warmup emails/day: $159/month
3. Lemwarm by Lemlist
Lemwarm is the built-in email warmup engine of Lemlist, a popular prospecting tool. It helps new inboxes build a strong reputation while allowing users to combine warmup and prospecting within a single platform. Lemwarm is highly recommended for users who already use Lemlist or want an all-in-one solution.
Key Features:
- Personalized warmup based on your sending volume
- Emails automatically sent, replied to, and marked safe
- Deliverability score and performance analysis
- Natively integrated into Lemlist’s campaign system
Pricing:
- Included in Lemlist’s Standard plan: $59/month
4. Instantly.ai
Instantly is an all-in-one cold email platform with built-in warmup functionality. It’s designed for scale, whether you’re a solo founder or managing dozens of inboxes. This warm up email provider ensures all your domains warm up safely before full prospecting starts, using intelligent inbox interaction patterns.
Key Features:
- Unlimited email warmups on every plan
- Smart warmup strategy based on ESP best practices
- Auto-saves emails from junk, flags them as important
- Warmup analytics integrated with prospecting performance
Pricing:
- Growth: $97/month (unlimited warmups & inboxes)
- Hypergrowth: $197/month (for teams with bulk prospecting)
5. Mailreach
Mailreach is a comprehensive warmup platform built for agencies, sales teams, and marketers who want advanced control and visibility into their email deliverability. It offers granular data and lets you customize the warmup pace to match your prospecting volume or risk level.
Key Features:
- Works with Gmail, Outlook, Zoho, and other ESPs
- Real-time inbox placement tracking and blacklist monitoring
- Scalable plans for single users or multiple inboxes
- Clean UI with historical performance and sender reputation metrics
Pricing:
- Solo Plan: $25/month (1 mailbox)
- Agency Plan: $59/month (multiple mailboxes & premium support)
6. Folderly
Key Features:
- AI-based warmup engine that adapts daily to send emails
- Junk and deliverability diagnostics
- Email content analysis and optimization suggestions
- Domain blacklisting alerts and deliverability score
Pricing:
- Starts at $200/month (custom pricing for agencies and large orgs)
7. Warmy.io
Key Features:
- AI-powered warmup that adjusts email volume automatically
- Reputation dashboard and inbox placement reporting
- Email deliverability tools, including spam testing and domain health
- Supports Gmail, Outlook, SMTP, Yandex, and more
Pricing:
- Basic: $49/month (1 mailbox)
- Business: $129/month (5 mailboxes)
- Agency: Custom pricing
8. Allegrow
Allegrow is designed specifically for B2B sales and focuses heavily on real email folder placement testing. It gives users powerful insights into how their prospecting campaigns perform across different inbox providers. Ideal for sales leaders and marketing ops looking to optimize deliverability and email outreach for pipeline growth.
Key Features:
- Email warmup and placement scoring (Gmail, Outlook, etc.)
- Daily engagement to keep the sender score high
- Native CRM integrations (HubSpot, Salesforce)
- Enterprise-grade analytics and dashboards
Pricing:
- Custom pricing based on mailbox volume and company size
9. Growbots Warmup & Recovery
Growbots offers an add-on warmup and recovery feature within its outbound automation platform. This email warmup service helps new inboxes gain trust before sending campaigns and assists flagged domains in recovering deliverability. Perfect for sales teams using Growbots for cold email.
Key Features:
- Built-in warmup feature with volume scheduling
- Reputation monitoring for multiple accounts
- AI-based engagement mimicking real behavior
- Seamlessly integrates into Growbots outbound engine
Pricing:
- Warmup included in outbound plans starting at $49/month
10. QuickMail Auto-Warmer
QuickMail’s Auto-Warmer is one of the most popular free warmup tools. It uses a community of real inboxes to send and receive messages in a natural cadence. While it doesn’t offer as much data as premium tools, it’s a fantastic choice for startups or solo founders on a budget.
Key Features:
- 100% free warmup for up to 50 emails/day
- No manual setup required
- Works with Gmail, Outlook, and SMTP
- Auto-detection of spam issues and inbox feedback
Pricing:
- Free for 1 inbox (up to 50 emails/day)
- Pro Plan (with QuickMail cold outreach tools): $59/month
How to Choose the Right Warm-Up Tool
When choosing the email warm-up service for your needs, consider:
- Ease of Integration: Must connect smoothly with your email service providers.
- Scalability: Supports growing email sending volumes.
- Insight and Analytics: Offers data on email view rate, email folder placement, and spam rate.
- Customization: Allows control over the warm-up process.
- Ease of Integration: Must connect smoothly with your email service providers.
Picking a user-friendly cold email solution will help both beginners and experts build trust with ISPs and prospects alike.
Warm-Up Best Practices to Improve Your Email Deliverability
- Start Slow: Gradually increase volume to avoid red flags.
- Use Reputable Domains: Avoid using spammy or brand-new domains without a warmup.
- Authenticate Your Domain: Implement SPF, DKIM, DMARC.
- Monitor Feedback Loops: Keep an eye on bounce and complaint rates.
- Start Slow: Gradually increase volume to avoid red flags.
These deliverability best practices are essential for anyone who wants to reach the inbox consistently.
How Email Warmup Fits Into a Complete Prospecting Strategy
Email warmup isn’t just a one-time process. It’s an ongoing strategy that complements your entire email prospecting and email marketing efforts. As your email campaigns scale, keeping your sender reputation intact ensures long-term success.
Pairing email warm-up with deliverability tools for segmentation, personalization, and timing gives you a robust and future-proof prospecting engine.
Key Signs Your Email Warmup Is Working
- Higher Open Rates: Indicates good mailbox placement.
- Fewer Spam Complaints: Shows emails are being well received.
- Stable Sender Reputation: Consistency in delivery metrics.
- Positive Email Engagement: Higher replies, clicks, and read time.
- Higher Open Rates: Indicates good mailbox placement.
These indicators help you improve your sender reputation and know that your emails are reaching the right inboxes.
Conclusion
Whether you’re just starting cold outreach or scaling a sales team, email warmup is non-negotiable. With spam filters more sensitive than ever, even high-quality content won’t perform if your sender’s reputation is weak. Here is a quick overview:
Best for Beginners: Mailwarm
Best for Agencies: Mailreach or Folderly
Best Free Tool: QuickMail Auto-Warmer
Tip: Always pair email warm-up with targeted messaging, clean lists, and value-driven prospecting for the best results.
