Email Warmup Tools: What They Do and Which Ones Actually Work

If you're sending cold emails at scale, you need email warmup. Without it, your emails land in spam, your domain gets flagged, and your outreach campaigns go nowhere.

Email warmup tools gradually increase your sending volume while simulating natural email activity-sending messages, getting replies, moving emails out of spam. This builds your sender reputation with email providers like Gmail and Outlook so your actual outreach emails hit the inbox.

I've tested most of the major warmup tools. Here's what you need to know about pricing, features, and which ones are worth using.

What Email Warmup Actually Does

Email warmup tools connect to your email account and automatically send emails to other accounts in their warmup network. Those accounts reply, mark your emails as important, and move them out of spam folders. This creates positive engagement signals that email providers use to determine if you're a legitimate sender.

Without warmup, a brand new domain sending 100+ cold emails per day looks suspicious. Email providers throttle your delivery or send you straight to spam. Warmup makes your sending patterns look gradual and natural.

You need warmup for new domains, new email accounts, or any account that hasn't been sending regular email. Even established accounts benefit from ongoing warmup if you're doing heavy cold outreach.

The process works by creating realistic email conversations between your account and thousands of other accounts in the warmup network. These emails get opened, replied to, and marked as important. If they land in spam, the warmup tool automatically moves them to the primary inbox. This trains email providers to recognize your domain as trustworthy.

Integrated vs Standalone Email Warmup Tools

Email warmup tools fall into two categories: standalone warmup services and integrated features in cold email platforms.

Standalone warmup tools like Lemwarm, Warmy.io, and Warmup Inbox charge per account (usually $15-50/month per account). They focus exclusively on warmup with detailed customization and monitoring. These make sense if you're using a cold email platform that doesn't include warmup, or if you want more control over the warmup process.

Integrated warmup in platforms like Smartlead, Instantly, and Reply is included with your subscription and typically allows unlimited accounts. These are more cost-effective if you're warming up multiple accounts, but offer less customization.

For most businesses doing cold outreach, integrated warmup makes more sense. You get everything in one platform, unlimited warmup accounts, and lower total cost. Only go with standalone warmup if you need advanced features or you're committed to a cold email platform that doesn't include warmup.

Smartlead Warmup

Smartlead includes unlimited email warmup as part of its cold email platform. You get warmup for unlimited email accounts on all plans, starting at $39/month for 6,000 leads.

The warmup runs automatically once you connect your email accounts. You can adjust the daily sending volume and ramp-up speed. Smartlead's warmup network includes thousands of real email accounts, and the system handles replies, spam folder interactions, and engagement automatically.

The AI-powered warmup emulates human conversations and automatically adjusts volumes based on your account's age and current reputation. Smartlead also automatically matches your email provider with that of your recipient-if you have both Gmail and Outlook accounts, it uses your Gmail account when sending to Gmail users for optimal deliverability.

What's good: Unlimited warmup accounts included with your subscription. No per-account fees. Built directly into the cold email platform so you're not juggling separate tools. The deliverability monitoring shows your sender score and flags issues. The platform provides DNS monitoring, blacklist checks, and sender reputation tracking all in one dashboard.

What sucks: The warmup settings are fairly basic compared to standalone tools. You can't customize conversation topics or email content as much. If you only need warmup without the full cold email platform, you're paying for features you don't use. Less granular control over ramp-up speeds and reply rates.

Best for: Anyone already using Smartlead for cold email who wants warmup included without extra costs. If you're sending from multiple domains with multiple accounts per domain, this is the most cost-effective option. Agencies and teams managing dozens of email accounts.

Try Smartlead's warmup features

Instantly Warmup

Instantly offers email warmup as part of its cold email software. Plans start at $37/month and include warmup for all connected accounts.

The warmup feature is called Unibox Warmup. It sends emails between accounts in Instantly's network, generates natural-looking replies, and gradually increases sending volume. You can set custom daily limits and adjust how aggressive the warmup should be.

Instantly's warmup network includes over 550,000 email accounts, providing extensive coverage across different email providers. The platform sends a random number of warmup emails daily and lets you choose specific open and response rates to match your target sending patterns.

What's good: Simple setup that takes about 2 minutes per account. The warmup runs in the background while you send campaigns. Unlimited warmup accounts on all plans starting at $37/month. Good deliverability tracking that shows inbox placement rates. Large warmup network provides diverse sender interactions.

What sucks: Like Smartlead, you're paying for the full cold email platform even if you only want warmup. The warmup conversations are generic and obviously automated if anyone actually reads them. Some users report the warmup is less effective for Microsoft/Outlook domains. A few reports of domains getting blacklisted with certain ESPs if settings are too aggressive.

Best for: Teams running cold email campaigns through Instantly who want integrated warmup. The platform works well if you need both functions in one place. Good for high-volume senders who need to warm up many accounts simultaneously.

Check out Instantly's warmup tools

Lemwarm by Lemlist

Lemwarm is Lemlist's standalone warmup tool, though it's also included with Lemlist's cold email plans. Pricing starts at $29/month for 5 email accounts, or it's included free with Lemlist Email Outreach plans starting at $59/month.

Lemwarm uses a network of real email accounts to exchange emails with your account. It customizes warmup conversations based on your industry and provides a deliverability score called Lemwarm Score that tracks your sender reputation.

The platform runs in a "black box" style, automatically determining email sending rates based on your domain age and sender reputation. You can add characteristics like industry, country, and email type for personalization. Lemwarm provides ESP-specific reports showing exactly how your email performs on Gmail versus Outlook versus Yahoo.

What's good: More natural-looking warmup emails compared to competitors. The conversations actually make sense if someone reads them. Good reporting on deliverability metrics broken down by email provider. You can use Lemwarm standalone without the full Lemlist platform. Contextual tips on how to further increase your deliverability rates.

What sucks: Expensive if you're warming up multiple accounts-$29 for 5 accounts, and pricing increases as you add more. The Lemwarm Score can be inconsistent and doesn't always reflect real-world inbox placement. Setup takes longer than other tools. On the Pro plan you can use your own email templates, but the default plan uses generic texts of mixed quality.

Best for: Solo senders or small teams with 1-5 email accounts who want higher-quality warmup conversations. Worth considering if you're already using Lemlist for cold email. Good for users who need deep visibility into ESP-specific performance.

Try Lemlist with built-in Lemwarm

Warmy.io

Warmy.io is a dedicated email warmup tool powered by an AI engine called "Adeline" that automates the mailbox warmup process. Plans start at $49/month, though exact pricing isn't published on their website-you need to book a consultation for detailed pricing information.

Warmy uses AI-driven warmup with real-time insights and can send up to 5,000 daily warmup emails on the Platinum plan. The platform supports warmup emails in over 30 languages, making it one of the few tools that can warm up emails in foreign languages beyond English.

The tool provides automated engagement including opens, clicks, replies, and automatically removes emails from spam folders. Warmy offers three warmup speeds: slow, medium, and fast, with slow being the recommended approach. The platform includes DNS record testing for SPF, DKIM, and DMARC, plus blacklist monitoring.

What's good: High-quality AI-generated warmup emails that look authentic. Very high daily warmup volume capacity for bulk senders. Multi-language support for international campaigns. User-friendly interface with clean dashboards. Dedicated deliverability consultant included on higher plans. 7-day free trial with 50 free warmup emails.

What sucks: Expensive compared to competitors-starts at $49/month and goes up to $429/month for the Platinum plan. Per-inbox pricing means costs add up fast when warming multiple accounts. Some users report the tool works better with Gmail than with Outlook or other providers. Advanced features only available on higher-tier plans. No free trial period offered currently.

Best for: Bulk email senders who need very high daily warmup volumes. Businesses running international campaigns that need multi-language warmup. Users who want AI-powered automation and don't mind premium pricing. Not ideal for agencies managing many client accounts due to per-inbox costs.

Warmup Inbox

Warmup Inbox is a budget-friendly standalone warmup tool with a network of over 30,000 real inboxes. Pricing starts at $9/month for 1 account when billed annually, or $15/month when billed monthly.

The platform emphasizes that it uses inboxes of only real people, making warmup communication extra natural. Warmup Inbox automatically engages with your emails by replying, marking them as important, and unmarking them as spam. The service tracks where your emails land across major providers like Gmail, Outlook, and Yahoo.

One standout feature is ESP-specific warmup-you can choose which email service providers to target during warmup, helping you build reputation with the providers that matter most for your audience. The platform also offers language-specific warmup capability.

What's good: Most affordable option for single-account users. Simple, straightforward setup. Large network of 30,000+ inboxes provides good coverage. Lets you warm up your own templates to maintain consistency. Free 7-day trial. Various free tools like DMARC Record Generator, SPF Generator, and Email Spam Checker.

What sucks: Per-inbox pricing model means costs increase quickly if you're warming multiple accounts. Network quality may vary since it relies on user-contributed inboxes. Limited advanced features compared to premium tools. Analytics only shows main inbox vs spam, doesn't differentiate promotions or other folders.

Best for: Freelancers and solo senders with 1-3 email accounts. Small businesses on tight budgets. Users who want basic warmup without complex features. Good starting point for beginners new to email warmup.

Mailivery

Mailivery is one of the few warmup tools that allows unlimited inboxes. Instead of charging per inbox, Mailivery charges based on your daily warmup volume. Plans start at $69/month for 100 daily warm-up emails.

Mailivery uses a peer-to-peer network of over 30,000 real email addresses-not fake or throwaway mailboxes. The AI-powered system generates meaningful content rather than generic "Lorem ipsum" text, and responds directly in the same thread rather than as separate messages.

The platform uses intelligent logic like avoiding weekend sends and sending during working hours in your time zone. Mailivery includes blacklist monitoring across 70+ blacklists, email verification, and comprehensive reporting showing where emails land in real-time. You can customize the volume and timing of warmups, and set custom templates on any paid plan.

What's good: Unlimited inboxes on all plans-pay for volume, not account count. Ideal for agencies and teams managing multiple clients. High-quality peer-to-peer interactions look more authentic. Custom warmup templates let you test your actual email content. Daily limit of 250 emails per inbox prevents abuse. Includes email verification and blacklist monitoring.

What sucks: More expensive than some competitors at $69/month minimum. Daily warmup email limits may not be sufficient for high-volume senders on lower plans. Some advanced users want more customization options. The ramp-up feature is helpful but not as granular as standalone tools.

Best for: Agencies managing multiple client accounts. Teams running outreach across many domains. Users who want peer-to-peer warmup with real human-like interactions. Businesses that need email verification and blacklist monitoring bundled together.

MailReach

MailReach is a warmup tool that specializes in deliverability testing and inbox placement monitoring. Pricing starts at $25/month per mailbox, with spam credits sold separately starting at $28 for 100 (though you get 20 free credits to start).

MailReach uses a network of 20,000+ inboxes from real accounts and leverages machine learning to optimize your deliverability. The platform offers both autopilot mode and customized settings, letting you choose starting volume, daily increase, and maximum volume for warmup emails.

A key feature is the ability to test inbox placement while warming up your accounts. MailReach automatically creates a folder named "To Follow" in your inbox to store all warmup messages, preventing inbox clutter. The platform provides detailed explanation of what to expect from warmup and sends updates on your sender reputation via Slack or Webhooks.

What's good: Strong focus on deliverability testing alongside warmup. Good balance of automation and customization. Read emulation feature scrolls through emails to simulate authentic interaction. Machine learning continuously optimizes performance. Quick registration and account connection. Automatic filtering of warmup messages keeps your inbox clean.

What sucks: Per-mailbox pricing gets expensive for multiple accounts. Spam credits are sold separately, adding to costs. No access to warmup results after subscription expires. Can't choose reply rate or use your own templates on basic plans. Steeper learning curve for beginners compared to simpler tools.

Best for: Users who want to test inbox placement while warming up. Teams that need detailed deliverability analytics. Businesses willing to pay premium prices for advanced features. Not ideal for high-volume operations with many accounts.

Folderly

Folderly markets itself as an email deliverability ecosystem rather than just a warmup tool. Pricing starts at $96 per mailbox per month, with a separate Inbox Insights product starting at $64/month. A free plan offers 2 tests per month.

Folderly goes beyond basic warmup by addressing all aspects of email deliverability. The platform starts with a comprehensive email deliverability audit and Folderly score that considers all email infrastructure components. It analyzes your emails for deliverability issues and helps devise plans to combat them.

The platform provides AI identification of spam triggers, monitors DNS settings, and gives daily counts of how many emails land in inboxes versus spam folders. Folderly performs daily inbox upkeep activities automatically and provides personalized, contextual tips based on your current inbox performance. Advanced algorithms allow you to reach the maximum deliverability potential in about 2 weeks.

What's good: Comprehensive approach to deliverability, not just warmup. Automatically identifies why emails land in spam with detailed explanations. Template checker scans for spam triggers Grammarly-style. Daily monitoring of inbox placement rates. DNS configuration tools and BIMI setup support. GPT-3 powered interactions imitating human behavior. Expert support from deliverability specialists.

What sucks: Significantly more expensive than pure warmup tools at $96+ per mailbox. Pricing can be confusing with multiple products. Overkill if you only need basic warmup. More complex feature set has steeper learning curve. No simple warmup-only option at lower price point.

Best for: Businesses with serious deliverability problems that need comprehensive solutions. Teams that want ongoing monitoring and optimization. Senders who need expert guidance on fixing infrastructure issues. Not suitable for budget-conscious users or those wanting simple warmup only.

Reply.io Warmup

Reply.io includes email warmup as part of its sales engagement platform. Plans start at $60/month and include warmup for connected mailboxes.

The warmup feature automatically sends and receives emails through Reply's network. It adjusts sending volume based on your account's age and current reputation. The platform provides deliverability analytics and alerts you to issues.

Reply.io monitors blacklists and sender reputation automatically. The warmup works well for both Gmail and Outlook accounts, and integrates seamlessly with Reply's multichannel outreach features including calls and LinkedIn automation.

What's good: Solid warmup performance for both Gmail and Outlook accounts. Good integration with Reply's multichannel outreach features. The platform monitors blacklists and sender reputation automatically. Included with sales engagement features so you get more than just warmup.

What sucks: More expensive than Smartlead or Instantly if you only care about cold email and warmup. The warmup settings are buried in the interface and not as prominent as dedicated tools. You can't use the warmup without subscribing to the full platform. Less focus on warmup-specific features compared to specialized tools.

Best for: Sales teams using Reply.io for multichannel outreach (email, calls, LinkedIn) who need reliable warmup included. Overkill if you just need basic email warmup. Good for established sales teams with budget for comprehensive sales engagement tools.

Explore Reply.io's warmup features

TrulyInbox

TrulyInbox positions itself as the most affordable email warmup tool with unlimited mailboxes at any plan level. Plans start at just $29/month, and there's even a forever-free plan available.

On the free plan, you can connect 1 email account and send 10 warmup emails per day. Paid plans allow you to connect unlimited mailboxes and scale up to higher daily volumes. TrulyInbox claims to help users achieve over 97% inbox placement within 4 weeks.

The platform mimics human-like sending behavior through a network of highly reputable inboxes. This naturally builds trust with ESPs and improves inbox placement rates. TrulyInbox provides a graphical reporting dashboard with granular insights into warmup progress, including deliverability tracking against various ESPs.

What's good: Most affordable unlimited mailbox option-just $29/month for the entry plan. Only tool offering a forever-free plan. Unlimited mailbox connections on all paid plans. Simple, focused on warmup without unnecessary complexity. Customization options for email sending volume, reply rate, and ramp-up rate. Good reporting dashboard.

What sucks: Relies on user-contributed inboxes which may vary in quality and reputation. Network may be smaller than enterprise solutions. Fewer advanced features compared to premium tools. Some users find the interface less polished than competitors. Limited ESP-specific targeting options.

Best for: Agencies and freelancers managing many client accounts on a budget. Small businesses wanting unlimited warmup without high costs. Users who need basic, reliable warmup without advanced features. Teams testing email warmup for the first time with the free plan.

Snov.io Warmup

Snov.io is primarily an email prospecting tool that includes warmup features as part of a comprehensive cold outreach suite. Plans start at $30/month and include email finder, verifier, drip campaigns, CRM, and LinkedIn automation alongside warmup.

The warmup feature includes mailbox rotation, AI-curated warmup, and email verification. Snov.io offers targeted warmup options, letting you prioritize engagement from specific providers like Gmail or Outlook. Pricing is broken up based on credits for prospecting and verification, mailbox warmups, and email volume limitations.

The Trial plan is free with 50 credits and one mailbox warmup. The Starter plan costs $30/month for three mailbox warmups and 1,000 credits. AI-powered suggestions help you avoid language that flags spam filters, and deliverability tests show if emails are landing in spam.

What's good: All-in-one solution combining prospecting, verification, and warmup. Targeted warmup lets you focus on specific ESPs. Gmail email tracker helps discover recipient habits. AI suggestions for avoiding spam triggers. Good value if you need the full outreach stack. Includes tools other providers don't offer.

What sucks: Per-mailbox warmup pricing within the broader platform. Not ideal if you only want warmup functionality. Credits system can be confusing. Lower warmup limits on entry-level plans. Integration complexity if you're already using other tools.

Best for: Teams wanting an all-in-one prospecting and outreach solution. Users who need email finding, verification, and warmup in one platform. Small teams just getting started with cold outreach who want everything bundled.

Saleshandy Warmup

Saleshandy focuses on two core functions: warmup and campaign automation. The platform includes automated warmup that starts with low-volume emailing and ramps up over time, plus domain rotation and automated email follow-ups.

Custom scheduling helps you meet specific sending needs, and sender rotation helps avoid spam filters. Email engagement tracking shows how recipients engage through open and click-through metrics. The platform is designed as a complement to existing email platforms or CRM rather than a comprehensive all-in-one solution.

What's good: Clean focus on warmup and campaign automation without feature bloat. Automated ramp-up handles volume increases safely. Domain rotation prevents any single domain from being overworked. Good engagement tracking for monitoring performance. Integrates well with existing tools.

What sucks: Not as comprehensive as full-featured platforms. May need to integrate with other tools for complete outreach stack. Pricing and features less competitive than Instantly or Smartlead. Smaller user community means fewer resources and integrations.

Best for: Teams that want warmup and basic automation without a complex platform. Users who already have a CRM and just need warmup capability. Businesses looking for straightforward tools that do a few things well.

What to Look for in Email Warmup Tools

Not all warmup tools are equal. Here's what matters:

Network size and quality: Bigger warmup networks mean more diverse email providers. You want your warmup emails going to Gmail, Outlook, Yahoo, and smaller providers-not just Gmail to Gmail. But size isn't everything-the quality of the network matters. Real, aged accounts with good reputations are better than thousands of throwaway addresses. Look for networks with at least 10,000+ accounts, ideally 20,000+.

Customization: Can you control ramp-up speed, daily volume limits, and conversation topics? More control means you can match the warmup to your actual sending patterns. Look for tools that let you set starting volumes, increase rates, maximum daily sends, and reply rates. The ability to use your own warmup templates is a bonus.

Spam folder interaction: Good warmup tools automatically move messages out of spam and mark them important. This is critical for building positive reputation signals. The tool should also open emails, click links, scroll through content, and perform other human-like actions that signal engagement.

Monitoring and reporting: You need visibility into your sender reputation, deliverability scores, and any blacklist flags. Without monitoring, you don't know if the warmup is working. Look for dashboards that show inbox placement rates, spam rates, engagement metrics, and trends over time. ESP-specific reporting (Gmail vs Outlook performance) is valuable.

Pricing model: Per-account pricing gets expensive fast if you're warming up multiple domains. Unlimited warmup included with cold email platforms is usually more cost-effective. Calculate your total cost based on the number of accounts you need to warm up. For 10+ accounts, integrated platforms like Smartlead or Instantly typically cost less than standalone tools.

Automation and intelligence: The best tools use AI to adapt warmup speed based on your account's response. They should automatically adjust if deliverability drops or if you're ramping too quickly. Look for tools that handle DNS checking, blacklist monitoring, and technical setup issues.

Email authentication support: Good warmup tools help you verify SPF, DKIM, and DMARC records are properly configured. Some even include generators for these records. Without proper authentication, warmup can't work effectively.

Do You Actually Need Email Warmup?

Yes, if you're doing any cold outreach at scale. Here's when warmup is non-negotiable:

New domains: Any domain less than 3 months old needs warmup before sending cold emails. Email providers don't trust brand new domains. Even if your domain is registered, without sending history it has zero reputation. Plan for at least 4 weeks of warmup for new domains.

New email accounts: Even on established domains, new email accounts need gradual warmup. Going from 0 to 100 emails per day overnight kills your deliverability. Each inbox needs its own reputation building period.

Low sending volume: If your domain typically sends 10 emails per day and you suddenly start sending 200, that's a red flag. Warmup helps you ramp up gradually. Email providers track sending patterns and sudden spikes trigger spam filters.

After a break: If an account stopped sending email for weeks or months, you need to warm it back up before resuming high-volume outreach. Dormant accounts lose their reputation over time.

After deliverability issues: If you've been landing in spam or had deliverability problems, warmup can help rebuild your reputation. This includes recovery from blacklists or spam complaints.

Before major campaigns: If you're planning a large outreach campaign, warm up your accounts first. Don't learn about deliverability problems after sending to your entire prospect list.

You probably don't need warmup if you're sending under 20 emails per day from an established account, or if you're only emailing people you already have relationships with. Warmup is specifically for cold outreach and high-volume sending.

How Long Does Email Warmup Take?

Plan for 2-4 weeks minimum before sending cold email campaigns. Most warmup tools start slowly-maybe 5-10 emails per day-and gradually increase over several weeks.

Newer domains need longer warmup periods. A brand new domain should warm up for at least 4 weeks before heavy cold outreach. Some experts recommend 8-12 weeks for maximum deliverability. Established domains with new accounts can often start sending in 2-3 weeks.

The warmup timeline depends on several factors: your domain age, your target sending volume, the quality of your warmup network, and how aggressive your ramp-up is. A typical warmup schedule looks like this:

Week 1: Start with 5-10 warmup emails per day. Focus on building initial positive signals.

Week 2: Increase to 15-25 emails per day. Continue building engagement patterns.

Week 3: Ramp up to 30-40 emails per day. Monitor deliverability closely.

Week 4: Reach your target warmup volume (typically 40-50 emails per day for accounts under 6 months old, up to 80+ for older accounts).

Don't rush it. Starting cold campaigns too early tanks your sender reputation and can take months to recover. The extra week or two of warmup is worth it. And remember: warmup isn't a one-time process. You should keep warmup running continuously while doing cold outreach to maintain your reputation.

Common Email Warmup Mistakes

Starting campaigns too early: The biggest mistake. Give warmup at least 2 weeks, preferably 4 for new domains. Your eagerness to start sending isn't worth destroying your deliverability. Sending cold emails before your warmup is complete can permanently damage your domain reputation.

Turning off warmup after starting campaigns: Keep warmup running continuously while you're doing cold outreach. It maintains your sender reputation even as you send campaigns. Cold emails typically have lower engagement than warmup emails, so ongoing warmup compensates for this.

Using the same warmup account for campaigns: Your warmup emails should come from the same accounts that send your campaigns, but don't exceed platform limits. Balance your warmup volume with your campaign sending to avoid overwhelming the account.

Ignoring authentication: SPF, DKIM, and DMARC records must be properly configured before warmup starts. Warmup can't fix missing email authentication. Check your DNS records and make sure everything is properly aligned before beginning warmup.

Warming up too aggressively: Some tools let you ramp up very quickly. Resist the temptation. Slower, gradual warmup looks more natural and builds better reputation. Jumping from 10 to 100 emails per day will trigger spam filters even with warmup running.

Using poor quality email lists: Don't test warmup with purchased lists or invalid emails. High bounce rates destroy your warmup progress. Always verify email addresses before sending, even during warmup.

Inconsistent sending patterns: Warmup works best with consistent daily activity. Don't send 50 emails one day and nothing for three days. Email providers value predictability and consistency.

Forgetting about content: Warmup helps with sender reputation, but it can't fix terrible email content. Avoid spam trigger words, keep your text-to-image ratio high (at least 80% text), and use reputable links. Test your templates with spam checkers.

Neglecting manual monitoring: Even with automated warmup, manually check where your test emails land. Send emails to your own accounts on different providers to verify inbox placement. Don't rely solely on warmup tool metrics.

Skipping domain age considerations: Brand new domains need 4-8 weeks of warmup. Domains under 6 months old need longer, more gradual warmup. Adjust your expectations and timeline based on domain age.

Email Warmup Best Practices

Start before you need to: Begin warming up your domains weeks before you plan to launch campaigns. This gives you buffer time if anything goes wrong. If you're planning a major outreach campaign for Q1, start warming up domains in Q4.

Warm up multiple accounts per domain: Don't put all your sending through one email account. Spread volume across 3-5 accounts per domain to stay under provider limits and reduce risk. If one account has issues, others can continue sending.

Use realistic warmup content: If possible, use warmup templates that match your actual campaign content. This helps email providers recognize your typical sending patterns. Some tools like Mailivery let you use custom templates for warmup.

Monitor multiple metrics: Don't just watch inbox placement rates. Track bounce rates, spam complaints, engagement rates, and blacklist status. A comprehensive view helps you catch problems early.

Match warmup to sending patterns: If you plan to send 100 cold emails per day, maintain 40-50 warmup emails per day ongoing. The ratio should be roughly 1:2 or 1:3 (warmup to cold emails).

Test across providers: Send test emails to Gmail, Outlook, Yahoo, and other providers your prospects use. Deliverability can vary significantly between ESPs. What works for Gmail might not work for Outlook.

Keep detailed records: Track when you started warmup, what settings you used, and how deliverability changed over time. This helps you optimize future warmup campaigns and troubleshoot issues.

Layer your approach: Use warmup as one part of a comprehensive deliverability strategy. Combine it with proper authentication, list hygiene, good content, and engagement tracking.

Technical Setup for Email Warmup Success

Before starting any warmup tool, make sure your technical foundation is solid:

SPF Records: SPF (Sender Policy Framework) authorizes specific servers to send email on behalf of your domain. Without proper SPF, your warmup is wasted effort. Your SPF record should include all servers that send email for your domain.

DKIM Signing: DKIM (DomainKeys Identified Mail) adds a digital signature to your emails proving they haven't been altered in transit. This builds trust with email providers. Every email you send should be DKIM signed.

DMARC Policy: DMARC (Domain-based Message Authentication, Reporting, and Conformance) tells email providers what to do with emails that fail SPF or DKIM checks. Start with a monitoring policy (p=none) and gradually move to quarantine or reject as your reputation builds.

Custom Tracking Domain: If using link tracking, set up a custom tracking domain rather than using your sending domain. This protects your main domain if tracking links are flagged. Some platforms handle this automatically.

Dedicated IP (for high volume): If you're sending more than 200,000 emails per week, consider a dedicated IP address. This gives you complete control over your IP reputation, though it requires careful warmup of the IP itself.

Proper DNS Configuration: Make sure all DNS records are properly configured and propagated before starting warmup. Use tools like MXToolbox to verify your setup. Check that there are no conflicting records.

Subdomain Strategy: Some teams use subdomains for cold outreach to protect their main domain. For example, use outreach.yourdomain.com instead of yourdomain.com. This isolates deliverability risk.

Measuring Warmup Success

How do you know if your warmup is working? Track these metrics:

Inbox Placement Rate: The percentage of emails landing in the primary inbox (not spam, promotions, or other folders). Target 80%+ inbox placement before launching campaigns. Most warmup tools provide this metric.

Spam Rate: The percentage of emails landing in spam folders. This should decrease over time during warmup. If spam rates increase or stay high, something is wrong with your setup.

Engagement Rates: Opens, replies, and clicks on warmup emails. Good warmup tools generate high engagement automatically. Watch for consistent engagement patterns-sudden drops indicate problems.

Bounce Rate: Should be near zero during warmup. If you're seeing bounces, check your DNS configuration and email authentication. Hard bounces indicate serious problems.

Sender Score: Tools like Warmy.io and Folderly provide proprietary sender scores. While not perfect, they give you a single number to track progress over time.

Blacklist Status: Regularly check if your domain or IP is on any email blacklists. Good warmup tools include automatic blacklist monitoring. Being blacklisted kills your deliverability instantly.

Delivery Time: If your emails are being delayed or queued by receiving servers, you may be warming up too aggressively. Delays (421 bounces) can retry for 72 hours, which is normal, but consistent delays indicate throttling.

Free vs Paid Email Warmup Tools

Some platforms offer free warmup options. Are they worth using?

Free options: TrulyInbox offers a forever-free plan with 1 email account and 10 warmup emails per day. QuickMail's Auto-Warmer is completely free but integrated into their cold email platform. Instantly and Smartlead include warmup free with paid plans.

Free tools work for testing or very small-scale sending. If you're only sending 10-20 cold emails per day from one account, a free tool might be sufficient. But there are limitations: smaller networks, fewer features, basic reporting, and limited support.

Paid tools: Offer larger networks, better customization, detailed analytics, and priority support. For serious cold outreach, paid tools are worth the investment. The cost of a warmup tool ($15-100/month) is minor compared to the revenue lost from emails landing in spam.

The best value is often integrated warmup in cold email platforms. For $37-60/month you get unlimited warmup plus full campaign management. Standalone paid tools make sense if you need advanced features or your current email platform doesn't include warmup.

Warmup for Different Use Cases

Agencies managing client accounts: Need unlimited warmup at predictable costs. Mailivery and TrulyInbox offer the best pricing for multiple accounts. Look for tools with team management features and client reporting.

SaaS companies doing product outreach: Need reliable, set-it-and-forget-it warmup. Smartlead and Instantly work well for ongoing campaigns. Integration with CRM and product analytics is valuable.

B2B sales teams: Need warmup integrated with multichannel outreach. Reply.io combines email warmup with calls and LinkedIn. Look for tools that fit your existing sales stack.

Freelancers and solo senders: Need affordable warmup for 1-3 accounts. Warmup Inbox and Lemwarm offer good value. Free plans from TrulyInbox work for very light usage.

High-volume senders: Need tools that can handle 100+ warmup emails per day across many accounts. Warmy.io supports up to 5,000 daily warmup emails. Instantly and Smartlead handle unlimited accounts.

International businesses: Need multi-language warmup. Warmy.io supports 30+ languages. Make sure your warmup network includes the countries and providers your prospects use.

Which Email Warmup Tool Should You Use?

If you're running cold email campaigns and need warmup for multiple accounts: Use Smartlead or Instantly. Both include unlimited warmup with cold email tools starting under $40/month. Smartlead has better deliverability features and AI-powered warmup optimization; Instantly has a cleaner interface and larger warmup network.

If you need warmup for 1-5 accounts and want standalone service: Consider Lemwarm at $29/month for 5 accounts if you value natural-looking warmup conversations and ESP-specific reporting. Warmup Inbox at $9-15/month per account works if you need budget-friendly basic warmup. Otherwise, you're better off with a full cold email platform that includes warmup.

If you're managing many client accounts on a budget: TrulyInbox at $29/month for unlimited mailboxes offers the best value for agencies and freelancers. Mailivery is another option if you need peer-to-peer warmup and advanced features, starting at $69/month.

If you need comprehensive deliverability solutions beyond just warmup: Folderly provides complete deliverability management including spam trigger analysis, infrastructure auditing, and expert support. Starting at $96/month per mailbox, it's expensive but worth it for businesses with serious deliverability challenges.

If you're already using a cold email platform: Check if warmup is included. Most modern platforms (Smartlead, Instantly, Reply, Lemlist) include it. If your current platform doesn't offer warmup, that's a sign you should switch platforms rather than paying for separate warmup.

If you're sending high volumes across many domains: Instantly or Smartlead provide the best combination of unlimited accounts and robust warmup. Mailivery works well if you need unlimited inboxes with volume-based pricing.

If you're just getting started with cold email: Go with a platform that bundles warmup, email verification, and campaign management. Smartlead offers the best value for unlimited accounts. Instantly is easier to learn if you're new to cold email. Both have better long-term ROI than piecing together separate tools.

Email warmup isn't optional for cold outreach. Factor it into your timeline and budget before launching campaigns. The tools that bundle warmup with cold email platforms offer the best combination of features and pricing for most businesses.

If you're comparing cold email platforms overall, check out our guide to the best cold email software for a full breakdown of features and pricing across all the major platforms.