7 Best Lemwarm Alternatives for Better Cold Email Deliverability

Lemwarm is often the default starting point for cold email teams. It’s built into Lemlist, easy to activate, and provides basic warm-up automation with minimal setup.

However, as your campaigns grow, with more inboxes, new providers, and higher stakes, Lemwarm reveals its limitations. 

You start to understand that the surface-level diagnostics give you little visibility into where your emails land, making it hard to rectify deliverability issues any serious sender will eventually run into.

If you’re managing multiple inboxes, sending across multiple providers, or just need better domain intel, you’ve likely outgrown Lemwarm.

This guide covers seven of the best Lemwarm alternatives, tools that offer more realistic warm-up activity, deeper diagnostics, broader ISP coverage, and pricing that makes sense even as your volume scales.

What to Look For in a Warm-Up Tool

Before you pick a Lemwarm alternative, it helps to understand what actually makes a warm-up tool effective and where some fall short. Here are the five key traits to evaluate:

1. Network composition

When evaluating a warm-up tool, don’t just look at network size; look at the makeup of the inboxes.

For B2B cold outreach, what matters is that the majority of interactions come from Google Workspace and Microsoft 365 business inboxes. These providers dominate professional email and weigh engagement from their own ecosystems much more heavily than signals from consumer accounts (Yahoo, AOL, etc.) or custom SMTP inboxes.

If a warm-up network is filled with consumer or generic addresses, it won’t meaningfully improve your chances of inboxing with Gmail or Outlook. The strongest tools keep their networks weighted toward trusted GWS and O365 inboxes, so the signals you generate actually match the environment your prospects use.

2. Warm-up behavior

A good warm-up flow should mimic the way humans actually interact with email. Most people think spam filters only scan for words or formatting, but Gmail and Outlook weigh engagement signals from their own customers: opens, replies, thread depth, timing, much more heavily.

That means warm-up patterns that are too perfect (identical replies, the same send times, predictable thread structures) quickly look automated and lose value.

When comparing tools, check how they randomize activity. A credible warm-up flow should:

• Vary open and reply rates
  
• Include ignored or dropped threads
  
• Use different reply timing and tone
  
• Avoid detectable patterns like the same subject keyword across all customers

The more organic the signals, the more trust you earn with providers like Google and Microsoft.

3. Diagnostic depth

Look for a warm-up tool that does more than raise your sender reputation. It also needs to work alongside a Spam Test so you can see how your actual campaigns perform.

For instance, MailReach’s Spam Test sends your actual emails (with your subject lines, CTAs, and HTML) into dozens of real inboxes to show if they land in Primary, Promotions, or Spam. 

Lemwarm misses the mark here. Its “spam checker” is superficial, focused on word lists or formatting, and doesn’t show true inbox placement across Gmail, Outlook, or other providers. In practice, that leaves you blind to the issues that matter most.

Top Lemwarm Alternatives

The tools below offer more control and smarter diagnostics, designed to reflect real inbox behavior. Here’s how they compare, and why they’re stronger picks than Lemwarm once you start scaling.

1. MailReach

MailReach is an email deliverability platform built specifically for B2B cold outreach. 

Unlike Lemwarm, which still leans on templated patterns (like the same subject keyword across customers) and offers only superficial diagnostics, MailReach strengthens reputation with more organic warm-up signals and backs it with true placement visibility and detailed deliverability diagnostics.

Features

• Simulates real conversations with varied content, reply patterns, and positive interactions (opens, replies, stars, spam removal) to build and maintain sender reputation, mirroring the exact engagement signals mailbox providers like Gmail and Outlook use to determine trust.

• Its peer-to-peer network is made up mostly of real Google Workspace and Office 365 inboxes, with an average reputation score of 95.17/100, giving you the exact engagement signals that matter for inbox placement.

• Send your email under real sending conditions to 30+ inboxes to show exactly where it lands with the Spam test, so you can fix issues before they hurt campaigns. This differs from most tools that use synthetic 'spam scores', which don’t reflect actual delivery behavior.

• For teams managing multiple inboxes, you can tag, monitor, and manage hundreds of mailboxes with API access and Slack alerts, which is ideal for agencies or larger outreach teams. 
  
  
• Set up DNS records and run SPF and DKIM checks easily. 

Pros

• High-quality warm-up network (mostly Google & Microsoft inboxes)  
• Accurate spam testing based on real inbox placement, not synthetic scoring models
• One system to tag, monitor, and course-correct inboxes in real time

Cons

• Not designed for newsletter/B2C deliverability
• Higher pricing than bundled tools, which may feel steep if you only manage a few inboxes or send low volumes. However, the diagnostic depth and trusted network quality justify the cost for B2B cold outreach senders.

What users say

Pricing

2. Warmbox

Warmbox improves sender reputation by simulating human-like inbox activity, sending, replying, rescuing from spam, and varying content with AI to mirror natural engagement.    

Unlike Lemwarm, which leans on templated patterns , Warmbox creates more realistic interactions across a private network of 35,000+ real inboxes, from diverse countries and providers, and doesn’t tie you to a specific cold email platform.

Features 

• Uses GPT to generate unique message bodies and responses. This avoids repetitive, templated content, which spam filters often recognize and penalize. AI variation makes Warmbox’s behavior harder to detect as automated.

• For experienced senders and agencies, Warmbox offers granular control over warm-up behavior, you can set sending volume, schedule, reply frequency, and even thread depth. This helps create more realistic activity, for example, some emails might get multiple replies over several days, while others die off naturally. 

• Supports Gmail, Microsoft 365, Yahoo, Zoho, and any custom IMAP/SMTP inbox. While this gives you flexibility to warm up across a wide range of providers, it’s worth noting that Gmail and Outlook don’t assign the same weight to activity from non-trusted or custom SMTP inboxes, so inbox quality matters more than sheer diversity.

• Monitors your DNS records (SPF, DKIM, DMARC) and alerts you if your domain is missing authentication or appears on spam blacklists, complete with alerts and reports. This helps proactively address issues that could hurt placement. 

Pros

• Generates unique messages and replies with GPT, avoiding repetitive templates.
• Offers full control over sending volume, schedule, reply frequency, and thread depth for realistic warm-up behavior.
• Works with Gmail, Microsoft 365, Yahoo, Zoho, and any IMAP/SMTP inbox.
• Doesn’t require using a specific cold email platform

Cons

• No built-in inbox placement testing, unlike MailReach, you won’t see exactly where your emails land.

Pricing

3. Warmy

Warmy is a deliverability-focused warm-up tool powered by its Adeline AI engine. Instead of static schedules, Adeline builds personalized warm-up plans for each mailbox, predicts optimal send times and volumes, and flags content with high spam risk. It also learns from network-wide data to adapt strategies automatically, giving more than just randomized sending, but an actively optimized warm-up flow.

Unlike Lemwarm, which lacks seed testing and detailed provider-level insights, Warmy shows you exactly where your emails are landing (inbox, spam, or promotions), through tests sent to real Gmail and Outlook inboxes, making it a stronger fit for teams who want both warm-up and visibility.

Features

• Sends test emails to real inboxes (seed accounts) across Gmail, Outlook, Yahoo, etc., then reports exactly where those messages landed.
  
  
• You can link your domain to Google Postmaster inside Warmy’s dashboard and track sender reputation, spam rate, and IP-level trust signals directly from Google’s own feedback. Note that Postmaster is best viewed as a domain health scorecard, not a placement diagnostic.
  
  
• Performs ongoing checks for SPF, DKIM, DMARC, MX, and DMARC alignment. It also monitors 100+ blacklists and sends alerts if your domain/IP appears.
  
  
• Before you send campaigns, Warmy analyzes your subject lines, message body, and HTML for known spam triggers and assigns a deliverability score.
  
  
• Spreads warm-up traffic across multiple providers (not just Gmail and Outlook), simulating the behavior of real-world traffic flows. 

Pros

• Improves deliverability for automated flows for abandoned cart, nurture sequences, though this benefits more e-commerce/marketing use cases than B2B cold outreach.  
• Automated warm-up process uplifts domain reputation without manual effort.
• User interface praised as excellent compared to other tools.

Cons

• Lacks real-world inbox-based placement across GWS/O365.
• Focuses on cosmetic features like template warmup and warmup by industry    

Pricing

They have not publicly disclosed pricing. Book a sales demo for more information.

4. Folderly

Folderly is designed for teams that need deep diagnostic data in addition to inbox warm-up. 

Unlike Lemwarm, it doesn’t rely on templated replies; instead, Folderly provides a full-stack deliverability toolkit, including seed-based inbox placement testing (via its ‘Inbox Insights’ feature), daily monitoring of domain health, spam triggers, and blacklist status, plus actionable recommendations.

Features 

• Sends emails to a distributed set of seed inboxes and scans your message for spammy words, broken links, poor HTML structure, or blacklisted domains. Note that this helps flag risks, but it doesn’t guarantee inbox placement visibility across real ESPs.
  
  
• Builds a report highlighting misconfigurations and risks, like misconfigured or missing DNS records.
  
  
• Simulates human interaction by sending, replying, rescuing emails from spam, and varying behavior across time. Note: this reflects Folderly’s internal test inboxes, not real Gmail/Outlook accounts.
  
  
• Uses multiple network clusters with reputation shielding to prevent pooled damage, which is ideal if you’re managing multiple domains or high-risk campaigns.
  
  
• Tracks domain health and warm-up performance over time with visual dashboards. This lets you monitor whether changes you make (like editing content or adjusting sending volume) are helping. 

Pros

• Clear insights, actionable tips, and spam trigger detection to pinpoint why emails miss the Primary inbox.
• Strong customer success team that’s responsive and proactive, even helping configure DNS and improve templates.

Cons

• Occasional need to adjust settings when deliverability fluctuates.
• Reports of account suspension or email sending issues.
• Very expensive compared to other tools on the list

Pricing

5. InboxAlly

InboxAlly focuses on increasing inbox placement through interaction simulation and deliverability training across a seed‑based network of internal inboxes. Since some of these may be free or custom SMTP setups, Gmail and Outlook may not fully weight those signals the way they would from established ESPs.  

Unlike Lemwarm, which is restricted to Lemlist users and cold email domains, InboxAlly lets you control engagement types, warm-up frequency, and ISP targeting, making it especially useful for marketers, cold emailers, and newsletter senders alike.

Features 

• InboxAlly opens, bookmarks, rescues messages from spam, and even scrolls and clicks to mimic human behavior, sending broader engagement signals. While simulated signals may help short-term, Gmail and Outlook weigh real human replies more heavily.
  
  
• You can choose to emphasize specific providers and adjust how much engagement each message gets. This helps when you're warming up for a particular audience.
  
  
• InboxAlly visualizes trends in engagement, inbox placement performance, and sender reputation health over time.
  
  
• You get support for multiple inboxes from different domains and platforms, unlike Lemwarm’s user base is narrower and mostly geared toward cold email.
  
  
• You can integrate with Gmail, Outlook, and any IMAP/SMTP provider. You’re not tied to one outreach tool, and API access allows integration into custom workflows. 

Pros

• Works with any sending platform and all email providers.
• Simulates real engagement (opens, clicks, replies) to build sender reputation.
• Compatible for warming up domains and IPs.
• Responsive, knowledgeable customer success team.
• Helpful for high-volume senders, cold outreach, and agencies.

Cons

• Limited native integrations with platforms like Salesforce, HubSpot, and ActiveCampaign (manual workarounds needed).
• Reporting could be more detailed.
• Some manual configuration required during setup for certain platforms.

Pricing

6. Smartlead 

Smartlead offers a native warm-up feature baked into its cold email platform. Unlike Lemwarm, which charges separately for every inbox, Smartlead warms up unlimited inboxes at no extra cost. 

It’s a solid option for teams already using Smartlead for outreach and looking for a scalable, hands-free warm-up across multiple inboxes.

Features 

• In contrast to Lemwarm, Smartlead users can warm up unlimited inboxes as part of their base plan, making it cost-effective for agencies or SDR teams managing large volumes.
  
  
• Warms up inboxes in a way that mimics real human behavior across multiple domains, using randomized sending patterns and reply behavior. While it doesn’t go as deep as Warmy or MailReach in mimicking human nuance (with scrolls, clicks), it’s more scalable than Lemwarm, which is constrained by its closed Lemlist network.
  
  
• Supports Gmail, Outlook, Zoho, Yahoo, and custom SMTP/IMAP inboxes—letting you simulate warm-up traffic across multiple ISP environments.
  
  
• Provides a general inbox health dashboard across connected inboxes. While Lemwarm offers basic diagnostics like SPF/DKIM/DMARC checks and blacklist alerts, Smartlead’s warm-up dashboard focuses on operational visibility rather than deep diagnostics.
  
  
• Schedules, reply timings, and language are randomized to avoid filters catching on.
  
  
• Automatically pauses inboxes that get flagged or blacklisted, limiting potential harm.

Pros

• Flexible campaign builder with multivariate testing.
• Advanced features like blacklist monitoring, custom tracking domains, and Spintax messaging.
• Responsive, proactive support team with Loom walkthroughs and real fixes.
• Private server options for enhanced control and client trust.
• Continuous product updates based on user feedback.

Cons

• Warm-up network relies heavily on custom SMTP mailboxes, limiting trusted Gmail/Outlook interactions for B2B deliverability
• Occasional Master Inbox bugs or syncing delays.

Pricing

7. Warmup Inbox

Warmup Inbox is a standalone warm-up tool that automatically sends, receives, replies, and rescues emails across a network of over 30,000 real inboxes. 

Unlike Lemwarm, which is limited to Lemlist users and domains often associated with cold outreach, Warmup Inbox interacts with a broader mix of inbox types across providers, making its warm-up activity more natural and effective at simulating real email traffic.

Features 

• Your emails engage with real, active inboxes on Gmail, Outlook, Yahoo, and others. This diversity gives you a healthier footprint across multiple ISPs, unlike Lemwarm’s narrow Lemlist-only loop.
  
  
• The tool gradually increases your sending volume while randomizing message timing, length, and replies. This helps mimic real conversations and prevents filters from flagging repetition.
  
  
• You get a dashboard that shows where your emails land based on real inbox interactions. While Lemwarm offers a general deliverability score, it lacks detailed placement visibility across providers.
  
  
• Warmup Inbox retrieves your messages from spam folders and replies to them, sending trust signals to mailbox providers. This behavior helps “train” filters to trust your domain.
  
  
• You can connect any email provider via IMAP/SMTP, including custom domains and legacy systems. Lemwarm is OAuth-based and works best with Gmail and Outlook, offering less flexibility with other setups.

Pros

• ESP-specific reputation reports like sender health, domain score, and blacklist status for Google and Outlook.
• Quick setup (often under 15 minutes).

Cons

• Interface feels basic to some users.
• No CRM or outreach features.
• Billing and package options can be confusing, especially when matching plans with usage needs

Pricing

Finding the Right Fit for Your Warm-Up Needs

Lemwarm might be enough when you're starting, but if you're sending at scale or troubleshooting inbox issues, it quickly shows its limits.

Its basic reporting and lack of inbox placement visibility can leave you guessing when your emails don't land.

The tools we’ve covered here give you more control, clearer data, and broader coverage, so your warm-up efforts actually match the way your real emails behave. 

If you target professionals and need the strongest sender reputation with Google Workspace and Microsoft 365, MailReach is the better fit. It gives you full placement visibility, continuous monitoring, and efficiency features designed for multi-inbox B2B teams. 

‍See how MailReach compares.