Warmy.io Alternatives for B2B Senders (2025 Edition)

When you’re leading B2B outreach, whether for your audience or prospective clients, your warm-up tool is the difference between reaching decision-makers and watching campaigns die in spam. Warmy.io is often a first stop because it’s quick to set up and gets your inbox sending right away. 

But once you’re running multiple inboxes or higher-volume outreach, it’s hard to continue with a tool that may not be built for your use case (B2B sending), and gives you almost no visibility into why dips in deliverability. 

That’s why we’ve looked beyond Warmy for this guide, not just at what tools claim to do, but at what they deliver in real-world cold email sending. We built this list with two filters:

• Technical configuration: warm-up volume, quality of inbox network, depth of deliverability diagnostics.

• Real user experience: what people find out after using the tool, including the gaps you won’t see on the sales page.

Each tool in our final list offers something Warmy doesn’t, from flat-rate unlimited inboxes to advanced spam placement testing. 

And because MailReach is purpose-built for serious B2B cold email teams, we’ll call out where it outperforms every other option so you can decide whether to skip the trial-and-error and go straight to the top.

Need a free spam test before you even sign up for a tool? Try it here.

5 Warmy.io Alternatives for B2B Senders

MailReach

MailReach is the alternative that solves the key deliverability issues Warmy overlooks. 

It offers an email warmup network of high-reputation Gmail (Google Workspace) and Outlook (Office 365) inboxes, along with an inbox spam placement test that shows exactly where your emails land and why. 

With built-in alerts, blacklist monitoring, and API access, it scales effortlessly, whether you’re an agency managing clients or an in-house marketing team. Choose this if you’re looking for a Warmy alternative that actually gives you control over your email deliverability.   

Features

• Uses a vetted network of active, high-reputation Gmail (Google Workspace) and Outlook (O365) inboxes to build genuine sender trust.

• Automatically warms multiple inboxes with smart pacing to match sending behavior.

• Tests spam placement across Gmail, Outlook, Yahoo, and 30+ inboxes, so you know exactly where you land.

• Performs deep SPF, DKIM, and DMARC checks, and gives actionable fixes when issues are found.

• Provides granular diagnostics to pinpoint deliverability issues like broken DNS records or reputation flags.

• Designed for B2B teams who need both warm-up and continuous deliverability monitoring in one platform.
  

• Sends automated alerts when deliverability drops, so you can take action before campaigns are impacted.

• Offers API access for scaling warm-up, monitoring, and reporting across multiple inboxes.

Why teams choose MailReach 

• Consistently improves inbox placement. Many users reported moving accounts from spam to inbox in under a month.
  

• Dedicated to deliverability only, giving it an edge over outreach tools with basic warm-up add-ons.

• Trusted support team that’s known for fast, hands-on help (yes, even from the founders). 

• Works with any email provider or platform and shows detailed inbox/spam placement trends.

Worth knowing 

• There’s no free trial—but we offer hands-on guidance from day one to get you set up fast and see results quickly.

What users say 

Pricing

Take a deeper look at their pricing. 

Warmup Inbox 

If you like Warmy’s simplicity but not its price tag, Warmup Inbox is its leaner, more affordable cousin—a fit for solo senders or small teams looking to keep a few inboxes healthy, without all the extra tooling. 

The trade-off is that you’ll get almost no diagnostics or placement testing. You’ll know your emails are being “warmed”, but you won’t see whether Gmail or Outlook is still routing you to spam. For senders who just need basic protection and reputation lift, and aren’t managing large volumes, that may be enough.

Features

• Connects your account to a peer-to-peer network of 30,000+ real inboxes for opens, replies, and spam recovery. 

• Uses gradual volume increases warm-up volume to build your sender reputation safely.
  
  
• Calculates a Dynamic Reputation Score for each inbox and compares it against a network benchmark.
  
  
• Provides multiple inboxes support and API access for centralized and automated management.
  
  
• Offers email alerts when your Reputation Score drops, so you can pause sending before issues escalate.

Why users choose Warmup Inbox

• Setup is quick — most users are up and running with warm-up emails in under 15 minutes.

• Includes basic ESP-specific scoring to highlight changes across Gmail, Outlook, and others. 

What to keep in mind 

• Pricing can scale quickly if you’re warming more than a few inboxes.
• Billing tiers and plan details may feel unclear at first.
• Doesn’t provide inbox placement testing or spam diagnostics.

What users say 

Pricing

Lemwarm

For Lemlist users, Lemwarm is the most seamless alternative to Warmy. It runs inside your outreach platform, pulls deliverability data into your campaign view, and provides basic reputation insights directly in the dashboard. Some customization features (like industry-themed templates) are available, though they’re largely cosmetic and offer limited real-world value. 

The bigger limitation: demwarm doesn’t show you exactly where your emails land (Inbox, Spam, Promotions), and warm-up volume is capped—just 40 emails/day per inbox on the base plan. It also requires an active Lemlist subscription, which locks you into one ecosystem.

By contrast, MailReach delivers broader visibility (30+ inbox spam placement testing), works with any sending setup, and avoids the bloat of features that don’t improve deliverability.

Features

• Official add-on of the Lemlist outreach platform, combining warm-up and campaign management in one workspace.
  
  
• Sends warm-up emails through Lemlist’s internal network of real inboxes to mimic actual engagement.
  
  
• Adjusts warmup volume based on your sending patterns to avoid volume spikes.
  
  
• Delivers warm-up progress tracking and basic reputational insights right within Lemlist’s dashboard.
  
  
• Uses AI-driven warm-up strategies tailored to your campaign rhythm. 

Why some Lemlist users stick with Lemwarm 

• Seamless if you’re already using Lemlist for outreach.
• Automates daily warm-up using real inbox engagement.
• Easy to connect and requires minimal configuration.
• Flags basic DNS issues early for quick fixes.

What to keep in mind 

• Some advanced features are locked behind higher-tier plans, but they add little value for deliverability, like custom templates or cosmetic options.
• Warm-up volume is capped and you never see whether emails land in Inbox, Spam, or Promotions, leaving a blind spot in deliverability.

Pricing

Warmbox 

Warmbox appeals to anyone who wants more control than Warmy gives without losing that “connect and go” feel. Its sizable inbox network, GPT-generated emails, and adjustable warm-up schedules make it more flexible than Warmy’s fixed automation. It’s also cost-effective at scale for a handful of inboxes. 

But while Warmbox lets you tweak the knobs, its analytics are still surface-level — you won’t get the deep spam diagnostics needed to solve stubborn placement issues. 

Features

• Offers flexible email warm-up schedules that mimic human sending patterns like gradual ramp-up or random timing.
  
  
• Uses a network of 35,000+ inboxes and GPT-4-generated email content to create realistic engagement.
  
  
• Provides basic monitoring of spam scores and domain health.

• Includes blacklist and DNS checks to flag technical issues proactively.
  
  
• Works with Gmail, Outlook, and other ESPs through  SMTP/IMAP.

Why users choose Warmbox 

• Lets you fully customize warm-up speed, volume, and engagement actions.

• Works with any email provider without extra integrations.

• Offers a simple dashboard to track reputation changes over time.

• Provides one-click pause or adjust for specific inboxes.

What to keep in mind 

• Analytics stay surface-level. While you can tweak schedules and content, you won’t get the deeper diagnostics needed to troubleshoot stubborn placement issues.

• Users report emails landing in spam after use, especially with Gmail.
  
  
• The support team is often unresponsive, even for billing issues.
  
  
• Network seems to rely heavily on Gmail inboxes, limiting its diversity.
  
  
• Limited product updates; innovation appears to have slowed.

Pricing

InboxAlly 

InboxAlly is designed for senders moving serious volume and willing to invest to fix deliverability fast. 

Instead of peer-to-peer warming, it simulates real user engagement through a large seed-list model: opens, scrolls, clicks, replies, and even marking emails as important. That activity helps train inbox providers like Gmail and Outlook to trust your domain, with many users reporting placement improvements within 4–14 days. 

The tool is easy to implement, platform-agnostic, and doesn’t require access to your inbox. But the cost puts it out of reach for most SMBs, and it still won’t fit neatly into every team’s workflow. MailReach offers a middle path, enterprise-grade spam testing, diagnostics, and network quality without InboxAlly’s price cliff.

Features

• Compatible with any email provider or platform — no inbox access needed.
  
  
• Simulates genuine engagement with actions like opening, scrolling, clicking links, replying, and marking emails as important.
  
  
• Removes emails from spam or promotions folders to train inbox providers toward primary placement.
  
  
• Works with your own email content and supports large list sizes without needing account access.
  
  
• Lets you create or use preset engagement profiles and control sending schedules, time zones, and open timing windows.
  
  
• Tracks deliverability trends over the last 30 days with a dashboard showing inbox, spam, and promotions placement.

Why teams choose InboxAlly

• Shows noticeable improvements in inbox placement within 4–14 days, based on real customer feedback.

• Simulates genuine engagement: opens, clicks, replies, spam removal—to teach inbox providers to trust your emails.

• Works with any sending platform and doesn’t require account access.

• Interface is praised for simplicity and speed to launch.
  
  
• Can handle multiple sender profiles and high interaction volumes.

What to keep in mind 

• Pricing starts at $149/month, which may be overkill for low-volume senders.

• Lacks diagnostic tools like spam placement testing, blacklist monitoring, and DNS checks.
  
  
• Limited native integrations with CRMs and ESPs (e.g. Salesforce, HubSpot, ActiveCampaign).
  
  
• Reporting shows where emails land, but doesn’t explain why—several users noted this gap.

What users say 

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Pricing

Note: Pricing details are based on publicly available information at the time of writing and may change. For the most accurate and current pricing, we recommend checking the provider’s official website.

Important Features to Look For in an Email Warm-Up Tool

Choosing a warm-up tool isn’t just about price or network size. For B2B senders, where a single deliverability dip can stall the pipeline, you need more than a “set and forget” checkbox. Here’s what to check before committing:

Real inbox network (not test accounts)

The warm-up network should include actual Google Workspace and Microsoft 365 inboxes, not free SMTP accounts or bots. Real inboxes mimic authentic engagement patterns, which mailbox providers value more.

Customizable warm-up behavior

Look for tools that let you control ramp speed, daily send limits, and engagement style. B2B teams sending to C-suite execs have different warm-up needs than e-commerce newsletters. 

Inbox placement testing

Warm-up alone doesn’t tell you if you’re landing in Gmail’s Primary tab or spam. A good email warmup tool runs placement tests across multiple providers and gives you a breakdown of inbox vs. spam vs. promotions.

Technical diagnostics (SPF, DKIM, DMARC, Blacklists)

Even a perfect warm-up won’t fix a broken DNS setup. Your tool should check SPF, DKIM, DMARC, and blacklist status—and ideally flag problems with actionable guidance.

Scalability for multiple inboxes

Agencies and sales teams often manage dozens of inboxes. Check for flat-rate pricing or volume discounts, plus centralized dashboards to track all accounts at once.

Transparent reporting and alerts

You shouldn’t have to guess whether warm-up is working. Look for real-time reputation scores, daily performance summaries, and alerts when something starts to slip, before it tanks deliverability.

Choosing the Right Warmy.io Alternative for B2B Senders

Warmy.io does a decent job at the basics, but most B2B senders outgrow it quickly once scale, complexity, and revenue stakes rise. The alternatives we’ve covered go beyond simply “warming” your inbox; they help you measure, diagnose, and fix the deeper issues that cause deliverability problems in the first place.

If your team is running multi-inbox outbound campaigns, managing deliverability for clients, or sending high-value B2B sequences, you need a tool that gives you control, visibility, and accuracy, not just activity for the sake of activity.

That’s where MailReach consistently pulls ahead. With its real inbox network, granular warm-up controls, detailed spam placement testing, and enterprise-grade reporting, it’s built for teams that can’t afford to guess at inbox performance.

Put simply: When inboxes drive revenue, “we sent and replied” isn’t enough. MailReach tells you what matters, and how to fix it.

‍Sign up for MailReach and see why serious B2B teams trust it to stay out of spam.