If you’re running B2B outreach, you know cold emails don’t work if they never hit the inbox. Email warmup tools promise to fix that, but there’s a flood of options—all sounding the same. This is for sales ops folks, marketers, and founders who want straight answers on whether tools like Mailivery are actually worth it, how they stack up, and what to keep in mind before you spend another dime on “deliverability.”
Why Email Warmup Matters (and Where It Goes Off the Rails)
First, quick reality check: Email warmup isn’t magic. It’s a workaround for the fact that new or dormant email accounts look suspicious to spam filters. If you start blasting cold emails from a fresh domain, don’t be surprised when you land in the junk folder.
Warmup tools try to fix this by simulating real conversations—sending, receiving, and replying to emails within a network of other users. The idea: train inbox providers (Google, Microsoft, etc.) to “trust” your account.
But here’s the catch: Not all warmup is created equal, and some of it borders on useless if used wrong. It’s a tool, not a cure-all.
Meet the Main Players: Mailivery and the Usual Suspects
Let’s break down the landscape. Here’s who you’ll run into most often:
- Mailivery: Automated warmup with a focus on realistic, human-like interactions.
- Mailreach: Large warmup network, lots of integrations, pretty hands-off.
- Warmup Inbox: Simple interface, lots of volume. Less control, but gets the job done for basics.
- Lemwarm (by Lemlist): Integrates with Lemlist’s outreach platform. Good for all-in-one folks, but pricier.
- Folderly: Full-service deliverability consulting, not just warmup.
- GMass Warmup (RIP): Used to be the go-to for Gmail, but Google shut down their API access in 2023. Worth mentioning so you don’t chase dead ends.
Pro tip: Ignore any tool that claims “guaranteed inbox placement.” That’s a red flag. No tool can override Google or Microsoft’s algorithms.
How These Tools Actually Work (And Where They Fall Short)
The Warmup Loophole
Every warmup tool works by creating a network of real (or semi-real) inboxes. Your email joins the club. The tool sends emails between members, marks messages as “Not Spam,” and sometimes replies. This signals positive engagement.
- Mailivery claims to use “AI-generated, human-like replies.” The theory: more natural conversations convince filters you’re legit.
- Others, like Mailreach and Warmup Inbox, focus on volume—lots of emails, but sometimes less realism.
- Lemwarm ties things to your Lemlist campaigns, aiming for a more “native” feel.
What nobody says out loud: These networks are only as good as their members. If you’re in a pool with mostly other cold emailers, the effect is limited. And if Google clamps down on certain tactics (which happens), you’re back to square one.
Integration and Automation
- Mailivery and Mailreach both offer one-click setup for Google and Microsoft accounts. No-fuss, which matters if you’re not technical.
- Some tools make you configure IMAP/SMTP settings—annoying and error-prone.
- Lemwarm simplifies things if you’re already using Lemlist for outreach.
Got a custom domain or non-standard setup? Check integrations before you buy. Some tools are Gmail/Microsoft-only.
Reporting and Deliverability Data
- Mailivery and Folderly provide detailed reports—where your emails land, how many get flagged as spam, etc.
- Warmup Inbox and Mailreach show more basic stats (volume, placement).
- Be wary of tools that promise “99% deliverability”—these numbers are easy to fudge.
What Actually Matters When Choosing (Cut Through the Noise)
Let’s keep it real. Here’s what’s worth your attention:
1. Network Quality > Network Size
- A giant network of fake or low-reputation inboxes won’t help. You want a tool whose warmup pool mimics real users, with solid sender reputations.
- Mailivery’s pitch is “AI-generated, human-like replies,” which, in theory, makes the interactions look more legit. That’s more useful than just blasting out thousands of predictable warmup emails.
2. Ease of Setup
- If it takes more than 15 minutes to connect your inbox, you’ll probably give up or screw it up. Mailivery and Mailreach are dead simple; others are hit-or-miss.
- Avoid tools that require you to fiddle with DNS or arcane settings unless you actually like that stuff.
3. Transparency
- Can you see where your emails land (inbox, spam, promotions)?
- Does the tool show why deliverability changes, or just spit out vanity scores?
- Folderly goes deep here (but at a big price). Mailivery is decent; Mailreach is basic but clear.
4. Price and Lock-In
- Some tools bundle warmup with outreach (Lemwarm/Lemlist). That’s fine if you use their platform, but overkill if you just want warmup.
- Watch for sneaky seat-based pricing. Mailivery, Mailreach, and Warmup Inbox all have per-inbox plans.
- Most don’t require long contracts, which is good—try before you commit.
5. Staying Power
- The email warmup space changes fast. Google and Microsoft can—and do—shut down tactics or APIs overnight.
- Tools like GMass Warmup got axed by Google; others may follow.
- Don’t build your whole process around a single tool. Use it as a boost, not a crutch.
When Warmup Can’t Save You (Common Gotchas)
Let’s get real: If your domain is brand new, your authentication is broken (no SPF/DKIM/DMARC), or your emails read like spam, no warmup tool will bail you out.
- Check your DNS records: Use an external tool (like MXToolbox) to make sure SPF, DKIM, and DMARC are set up right.
- Don’t send garbage: Warmup won’t help if your actual campaigns are full of spammy words, huge images, or sketchy links.
- Don’t over-warm: Sending hundreds of warmup emails per day from a new account is a red flag itself. Start slow.
Pro tip: Warmup works best before you start outbound campaigns. Use it for 2-4 weeks, ramp up gradually, and keep monitoring.
The Real-World Workflow: How to Use Warmup Tools the Smart Way
- Set Up Your Domain and Authentication
- Get your SPF, DKIM, and DMARC records sorted before you touch any warmup tool.
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Use a reputable domain. “Cheap throwaways” get flagged faster.
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Pick a Tool and Connect Your Inbox
- For most, Mailivery or Mailreach are the least painful to set up.
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If you’re all-in on Lemlist, Lemwarm is convenient (but pricey).
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Start Slow
- Let the tool send a few warmup emails per day. Don’t crank it to max on day one.
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Watch the reporting dashboard for signs of trouble (spam placement, bounces).
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Monitor and Adjust
- If your warmup emails are still hitting spam after two weeks, something else is wrong (check your DNS, content, or domain reputation).
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Don’t obsess over tiny fluctuations—look for big red flags.
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Gradually Layer in Real Outreach
- Once your deliverability is stable, start sending real campaigns.
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Keep warmup running in the background (at a lower volume) to maintain reputation.
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Keep It Clean
- Clean your lists. Bad data equals bounces, which tank reputation.
- Avoid links to sketchy sites or heavy attachments.
What to Ignore (And What to Watch Out For)
- Ignore “guaranteed inbox” claims: Anyone promising this is selling snake oil.
- Don’t chase shiny features: Most teams need warmup, reporting, and easy setup—nothing more.
- Watch for burn-and-churn tactics: If the tool encourages aggressive sending or “hacks,” run.
So, Is Mailivery Worth It? (And When Should You Use Something Else?)
If you want a straightforward, easy-to-use warmup tool that focuses on realism over brute force, Mailivery is solid. It’s not the cheapest, but you’re paying for a network that tries to mimic real conversations, not just volume.
- Best for: Teams launching new domains, scaling outreach, or fixing mild deliverability issues.
- Not magic for: Burned domains, spammy campaigns, or people looking for a one-click fix.
If you just need the basics, Warmup Inbox or Mailreach might be enough. If you want deep consulting, Folderly is overkill for most, but worth it if you’re sending big enterprise volumes and your emails have to land.
Bottom Line
Don’t overthink this: Pick a tool that’s easy to set up, has a reputation for realism, and doesn’t lock you in. Spend more time on your content and list quality than obsessing over dashboards. Warmup helps, but it’s not a silver bullet—so keep it simple, keep testing, and don’t believe the hype.