The Ultimate Guide to Best Email Warmup Tools (2025 Edition)

You spend hours crafting the perfect email. You have a great offer. You have a verified lead list. You hit "Send."

And then... silence.

No replies. No opens.

Why? Because your email never reached the prospect. It went straight to the Spam Folder.

This is the silent killer of modern businesses. If Google (Gmail) or Microsoft (Outlook) does not trust your domain, you are invisible. It does not matter how good your product is if no one sees it.

The solution to this problem is Email Warmup.

In this guide, we will break down the best email warmup tools available today. We will look at their features, pricing, pros, and cons. We will help you choose the right one to fix your sender reputation and get your emails into the Primary Inbox.

What Is Email Warmup? (And Why It Matters)

Many people misunderstand email warmup. It is not just about "sending emails."

Think of your email domain like a credit score. When you buy a new domain (e.g., alex@yourcompany.com), it has no credit history. It is neutral.

If you suddenly send 500 emails on Day 1, spam filters (like Google’s AI) see this as suspicious. They think, "This person is new and sending bulk messages. They must be a spammer." They block you immediately.

Email Warmup is the process of building that credit history.

It is a gradual process where you increase your email volume day by day. But volume isn't enough. You need engagement.

• You need people to open your emails.
• You need people to reply to your emails.
• You need people to mark your emails as "Important."
• Most importantly, if your email lands in Spam, you need someone to move it to the Inbox.

Doing this manually is impossible. You cannot ask 50 friends to reply to you every day.

Email Warmup Tools automate this. They join your email to a network of real inboxes. They send emails back and forth automatically. They simulate positive human behavior to teach Google and Outlook that you are a trusted sender.

11 Best Email Warm-Up Tools Reviewed

We have tested and analyzed the best email warmup services in the market. We looked at their network quality, ease of use, and results. Here is the complete breakdown.

1. Lemwarm

Lemwarm is often considered the pioneer of automated email warmup. It was created by the team behind Lemlist. Unlike cheap tools that just send random gibberish, Lemwarm focuses heavily on "Smart Warmup." It generates personalized conversations that look very human. It connects your inbox to a network of thousands of real users across the globe.

Key features:

• Smart Cluster: This is a unique feature. You can choose your industry (e.g., Marketing, Tech, Finance). Lemwarm will prioritize warming up your email with other people in that same industry. ‍
• Personalized Content: The emails sent between accounts are not random text. They are coherent sentences generated to look like real business inquiries. ‍
• Deliverability Score: A visual score from 0-100 that tells you exactly when you are ready to launch your campaign. ‍
• DNS Check: Automatically scans your SPF, DKIM, and DMARC records to ensure your technical setup is perfect.

Pros:

• The network quality is extremely high (fewer bots, more real humans).
• Very detailed reporting dashboard.
• Excellent for maintaining a high reputation over a long period.
• Trusted by major companies, adding to its reliability.

Cons:

• It is one of the more expensive options on the market.
• They do not offer a free trial (though it is included if you buy the Lemlist outreach tool).
• You pay per inbox, so costs scale up quickly if you have a large team.

Pricing:

• Essential Plan: Starts at $29/month per inbox. ‍
• Smart Plan: Starts at $49/month per inbox (includes advanced customization).

Verdict:

Best for Premium Reputation. If you have a high budget and cannot afford to take any risks with your domain, Lemwarm is the safest bet. It is the "Apple" of warmup tools—expensive but reliable.

2. Instantly.ai

Instantly disrupted the market by changing the pricing model. While others charge per email account, Instantly offers unlimited email warmup for a flat fee. This makes it the go-to choice for lead generation agencies and businesses that need to scale quickly. It combines warmup with a powerful cold email sending platform.

Key features:

• Unlimited Accounts: You can connect 1, 10, or 100 email accounts for one price. ‍
• Smart Focus: You can tell the tool to focus on specific providers (e.g., "My leads use Outlook, so warm up heavily against Outlook"). ‍
• Campaign Management: It is an all-in-one tool. You can warm up emails and send your cold outreach campaigns from the same dashboard. ‍
• Infinity Booster: A large pool of diverse email accounts to ensure your reputation grows fast.

Pros:

• Best value for money in the industry right now.
• Modern, clean, and very fast interface.
• The "Email Health" center gives great insights into why you might be landing in spam.
• Huge community and support network.

Cons:

• Customer support can be slow sometimes due to their rapid growth.
• It is a newer tool compared to Lemwarm, so it has less "historical" data.

Pricing:

• Growth Plan: Starts at $37/month (includes unlimited warmup accounts). ‍
• Hypergrowth Plan: Starts at $97/month (for huge volume).

Verdict:

Best for Scaling & Agencies. If you need to warm up more than 3 email accounts, Instantly is the clear winner. The unlimited model saves you hundreds of dollars a month.

3. Smartlead.ai

Smartlead is the biggest competitor to Instantly. It is built specifically for agencies and power users who manage hundreds of emails. It focuses on automation and robust infrastructure. Like Instantly, it allows for unlimited warmups and is designed to handle high volumes of cold email traffic without breaking.

Key features:

• Unlimited Warmups: Add as many sender accounts as you need. ‍
• Master Inbox (Unibox): A centralized inbox where you can see and reply to leads from all your different email accounts in one single view. ‍
• API Access: It has a very strong API, allowing developers to build custom solutions on top of it. ‍
• Auto-Mailbox Rotation: If an email account gets blocked or has issues, Smartlead can automatically pause it and switch to a healthy one.

Pros:

• Incredible for agencies managing client campaigns.
• White-label options available (you can brand the client dashboard with your logo).
• Very detailed analytics on open rates and reply rates.
• Uses natural AI conversations for warmup.

Cons:

• The interface has a steeper learning curve than Instantly.
• Setup can be slightly complex for a complete beginner.

Pricing:

• Basic Plan: Starts at $39/month (Unlimited warmup). ‍
• Pro Plan: Starts at $94/month.

Verdict:

Best for Agencies & Developers. If you run a lead generation company or need deeper technical control (API), Smartlead is the superior choice.

4. Warmy.io

Warmy is a fully automated tool that prides itself on being "AI-First." It uses an artificial intelligence engine named "Adeline" to manage your inbox interactions. Unlike other AI sales tools that are part of a larger sales platform, Warmy focuses 100% on deliverability and fixing damaged domains.

Key features:

• Adeline AI: The engine automatically adjusts the number of emails sent daily based on your domain's health. ‍
• Template Warmup: You can input your actual sales email template. Warmy will test it to see if your specific copywriting triggers spam filters. ‍
• Global Language Support: It can warm up emails in multiple languages, not just English. ‍
• Spam Removal: It physically moves your emails from the Spam folder to the Inbox, sending a strong trust signal to Google.

Pros:

• Very "hands-off" experience; the AI does the thinking for you.
• Includes many free tools like an email signature generator and SPF record checker.
• Great for international businesses due to multi-language support.
• Dashboard is visually appealing and easy to read.

Cons:

• Pricing is higher than the budget options.
• You pay per mailbox, which makes scaling expensive.

Pricing:

• Starter: Starts at $49/month per mailbox. ‍
• Business: Starts at $129/month.

Verdict:

Best for Automation Lovers. If you want a "set it and forget it" tool that uses high-tech AI to fix your reputation, Warmy is excellent, though pricey.

5. MailReach

MailReach is a specialized tool designed by email deliverability experts. While other tools focus on sending, MailReach focuses on diagnostics. It is famous for its "Spam Test" feature, which gives you a granular look at where your emails are landing (Inbox, Spam, Promotions, or Updates).

Key features:

• Spam Checker: Run a test before you launch a campaign to predict your deliverability. ‍
• Compatible with All Providers: Works seamlessly with Gmail, Outlook, Zoho, SendGrid, and custom SMTPs. ‍
• Smart Warmer: Uses a network of 20,000+ high-reputation human inboxes. ‍
• Reputation Monitoring: It tracks your domain reputation on major blocklists constantly.

Pros:

• The most accurate "Spam Test" on the market.
• Very easy to set up (takes about 2 minutes).
• Clean, data-rich dashboard that explains why you are in spam.
• Helps fix "Promotions Folder" placement, not just Spam folder placement.

Cons:

• No free plan available.
• It is a standalone tool, so you still need separate software to send your actual sales campaigns.

Pricing:

• Starter: Starts at $25/month per email account. ‍
• Scale: Starts at $19.50/month per account (if you buy in bulk).

Verdict:

Best for Spam Diagnostics. If you are confused about why your emails are failing, MailReach gives you the data you need to fix it.

6. Warmup Inbox

Warmup Inbox is a straightforward, no-nonsense tool. It does one thing and does it well: warms up your email. It connects to a massive network of over 20,000 real inboxes. It is perfect for freelancers or small business owners who want a simple solution without complex features they will never use.

Key features:

• Inbox Health Score: A simple daily score (0-100) that tells you the health of your domain. ‍
• Interconnected Network: A huge peer-to-peer network ensures diverse interactions. ‍
• Dynamic Ramping: Automatically increases send limits safely over time. ‍
• Blacklist Monitoring: Alerts you immediately if your IP address gets blacklisted.

Pros:

• Very affordable for single users.
• Setup is incredibly fast.
• Reliable and stable performance.
• Syncs with most major email providers easily.

Cons:

• Lacks the advanced reporting of Lemwarm or MailReach.
• No "unlimited" option for agencies.

Pricing:

• Basic: Starts at $19/month per inbox.

Verdict:

Best for Simplicity. If you just want a tool that works without a steep learning curve, this is it.

7. Folderly

Folderly is not just a warmup tool; it is a complete "Email Deliverability Solution." It is designed for enterprise companies and serious marketers who are facing severe spam issues. It goes deep into the technical infrastructure of your email to find root causes of bad deliverability.

Key features:

• Spam Trigger Detection: Analyzes your copy and subject lines to flag "spam words." ‍
• Infrastructure Audit: Checks your DNS settings (SPF, DKIM, DMARC, BIMI) deeply. ‍
• API Integrations: Connects with virtually any custom email setup. ‍
• Placement Analytics: Detailed charts showing your placement across different ISPs (Gmail vs Yahoo vs Outlook).

Pros:

• Extremely powerful for fixing domains that are already "burned" or blocked.
• High-level support from deliverability experts.
• Comprehensive approach that fixes technical errors, not just reputation.

Cons:

• Very expensive compared to competitors.
• Overkill for a beginner just starting out.
• The interface can be overwhelming with data.

Pricing:

• Starter: Pricing varies, usually starting around $49/month up to $200/month depending on the package.

Verdict:

Best for Enterprise & Fixing Burned Domains. If your domain is in big trouble, Folderly is the hospital you go to for surgery.

8. TrulyInbox (Saleshandy)

TrulyInbox is the warmup solution recommended by Saleshandy, a popular cold email platform. It is designed to mimic human behavior perfectly. It is unique because it offers a very flexible pricing structure and integrates tightly with the Saleshandy ecosystem.

Key features:

• Email Ramp-Up: Customizable daily limits to slowly build trust. ‍
• Smart Reply: The tool replies to a percentage of warmup emails to create "conversation threads." ‍
• Tagging: It automatically tags warmup emails so they don't clutter your main inbox. ‍
• Saleshandy Integration: Works flawlessly if you use Saleshandy for outreach.

Pros:

• Cost-effective compared to premium tools like Lemwarm.
• Good user interface that is easy to navigate.
• Effective at moving emails from "Promotions" to "Primary."

Cons:

• User reviews on support response time are mixed (G2 rating averages lower than competitors).
• Fewer advanced features than Smartlead or Instantly.

Pricing:

• Paid: Starts around $22 - $39/month (Pricing often bundled or tiered).

Verdict:

Best for Saleshandy Users. If you already use Saleshandy, using their native warmup tool makes sense for integration.

9. Warmbox

Warmbox is a tool for the tech-savvy marketer who loves customization. It gives you granular control over every aspect of the warmup process. It uses GPT-4 (AI) to write the content of the warmup emails, making them indistinguishable from real human emails.

Key features:

• Scenario Selection: Choose from different "recipes" (e.g., "Grow fast," "Maintain," "Custom"). ‍
• Provider Selection: You can choose to send emails specifically to Gmail, Outlook, iCloud, or Yahoo. ‍
• Timezone Control: Set the tool to only send emails during working hours in your target country. ‍
• GPT-4 Content: High-quality AI writing for email bodies.

Pros:

• Incredible level of control and customization.
• Very realistic email content.
• Beautiful, futuristic dashboard design.
• Great for targeting specific email providers.

Cons:

• Can be a bit complex for users who just want a simple "On" button.
• Pricing is per inbox, so scaling is costly.

Pricing:

• Solo: Starts at $15/month per inbox. ‍
• Startup: Starts at $69/month for 3 inboxes.

Verdict:

Best for Customization. If you want to control the exact speed, timezone, and target of your warmup, Warmbox is your tool.

10. Allegrow

Allegrow approaches warmup differently. It integrates directly inside your email sending platform (like Salesloft or Outreach). It acts as a "Safety Net." It monitors your activity in real-time and stops you from sending bad emails that could hurt your reputation.

Key features:

• Safety Net: Automatically pauses your campaigns if your reputation drops. ‍
• Inbox Placement Data: Shows you exactly what percentage of your emails hit the primary inbox. ‍
• Content Testing: A/B test your subject lines for deliverability before you send. ‍
• Real B2B Network: Focuses on B2B inboxes for higher relevance.

Pros:

• Unique "safety" features that prevent accidents.
• Integrates well with enterprise sales tools.
• High-quality B2B network.

Cons:

• Pricing is often customized and opaque (usually higher end).
• Geared more towards large sales teams than solo founders.

Pricing:

• Custom: Contact sales for pricing (Typically Enterprise level).

Verdict:

Best for Large Sales Teams. If you use Salesloft or Outreach and have a team of SDRs, Allegrow is essential insurance.

11. Mailwarm

Mailwarm is the "OG" (Original Gangster) of the warmup world. It has been around a long time. It is very simple and effective. It relies on a straightforward peer-to-peer network. However, it has not updated its features or pricing as aggressively as newer competitors.

Key features:

• Auto-Interaction: Opens, replies, and marks as important. ‍
• Dashboard: Visualizes your daily activity. ‍
• Pause/Resume: Easy control over activity.

Pros:

• Proven track record; it works.
• Extremely simple to use.

Cons:

• Very Expensive: It costs significantly more than tools like Instantly or Warmup Inbox for fewer features.
• Small network size compared to newer giants like Lemwarm.

Pricing:

• Starter: Starts at $69/month.

Verdict:

Good but Overpriced. It works well, but it is hard to recommend when competitors offer more features for half the price.

Paid vs. Free Email Warmup Tools: Which One Do You Need?

Is it worth spending money on a warmup tool? The answer depends on your goals and your risk tolerance. While free options exist, they come with hidden costs that can affect your long-term success.

When to Use a Free Email Warm-Up Service

A free tool is a good starting point if you have low volume and zero budget. Stick to free plans if:

• You are a beginner: You are just testing the waters of cold email. ‍
• You have low volume: You send fewer than 20 emails per day. ‍
• You have a single account: You only need to warm up one email address.

When to Invest in a Paid Service

Paid tools are insurance for your business. They offer better security and results. Upgrade if:

• Email drives your revenue: You cannot afford for your sales emails to land in spam. ‍
• You are scaling up: You need to send 50+ emails daily. ‍
• You manage multiple domains: You are an agency or have a sales team. ‍
• You need a reputation fix: Your domain is already blacklisted, and you need aggressive repair.

The Hidden Risk of Free Tools: "Free" often means "low quality." Some free tools use networks filled with fake bot accounts or spammers. If you warm up your email alongside spammers, Google may link your reputation to theirs. This can actually lower your deliverability score. Paid tools invest in high-quality, peer-to-peer networks of real humans.

How to Choose the Right Tool

Don't get overwhelmed. Follow this simple 3-step guide:

1. Count Your Emails: How many email addresses do you need to warm up? If it is more than 5, look at Instantly or Smartlead. If it is just 1, Lemwarm or Warmbox are great. ‍
2. Check Your Budget: Can you afford $30/month? If yes, go for a paid tool. It is safer. If not, start with QuickMail. ‍
3. Look for "Real" Emails: Ensure the tool uses a "Peer-to-Peer" network. This means real people's inboxes, not fake bot accounts.

Step-by-Step Setup Guide (Works for Most Tools)

Ready to start? Here is how you set up an email warmup tool in 5 minutes.

Step 1: Connect Your Email Sign up for the tool. You will need to connect your email provider (Gmail, Outlook, etc.). You might need to enable "IMAP" in your email settings. This allows the tool to send emails for you.

Step 2: Technical Check (DNS Records) The tool will ask you to check your "Records." These are:

• SPF: Like an ID card for your email. ‍
• DKIM: A digital signature. ‍
• DMARC: Instructions for spam filters.

• Don't worry: The tool will usually give you a code to copy and paste into your domain host (like GoDaddy or Namecheap).

Step 3: Set Your Limits Tell the tool how many emails to send.

• Recommendation: Start with 5 emails per day. ‍
• Ramp Up: Increase by 2-3 emails per day. ‍
• Max Limit: Stop around 40-50 emails per day for a dedicated cold email inbox.

Step 4: Enable "Read Emulation" If the tool has this feature, turn it on. It makes the bot "scroll" through your email before closing it. This looks very human.

Step 5: Let It Run Wait at least 14 days before you start sending your own sales emails. Keep the warmup tool running in the background forever. This maintains your reputation.

Expert Tips for Maximum Deliverability

Using a tool is not enough. You also need to follow these rules:

• Never use your main domain: If your company is acme.com, do not use that for cold email. Buy tryacme.com or getacme.com instead. If you get blocked, your main business email stays safe. ‍
• Keep it short: Spam filters hate long emails with big words. Write like you talk. ‍
• Limit links: Do not put 5 links in your first email. One link is enough. Zero links is better. ‍
• Don't use spam words: Avoid words like "Free," "Buy Now," "Cash," "100%," or "Guarantee" in your subject line. ‍
• Monitor your "Health Score": Check your tool once a week. If your score drops below 90%, stop your campaigns and let the warmup tool fix it.

Conclusion

Email warmup is not optional anymore. If you want your emails to reach the inbox in 2025, you must warm up your domain.

The tools listed above make it easy.

• For unlimited scaling, choose Instantly.
• For premium reputation, choose Lemwarm.
• For free starting, choose QuickMail.

Don't let your hard work end up in the spam folder. Invest in a tool, set it up once, and enjoy higher open rates.