If you’re sending cold emails or running B2B campaigns, you already know: getting into the inbox isn’t a given. The right deliverability testing tool can save your campaigns from the spam folder—but picking one isn’t as simple as grabbing the first shiny product you see on a listicle. This guide is for marketers, sales pros, and founders who want real answers, not marketing fluff, on how to choose the best email deliverability testing tool for your B2B go to market strategy.
Why Deliverability Tools Actually Matter (and What They Can’t Do)
Let’s be clear: no tool is a magic bullet. Deliverability testing tools help you spot issues like blacklisting, spam triggers, and technical missteps before your campaigns go live. They won’t fix your email content, heal a trashed domain reputation, or trick Gmail into loving you. But they will show you where you’re screwing up, and that’s half the battle.
What these tools can do: - Show if your emails are hitting spam or inbox - Analyze technical setup (SPF, DKIM, DMARC) - Flag blacklists or authentication gaps - Test how your emails look on different providers - Offer actionable (sometimes) advice
What they can’t do: - Rewrite bad copy - Fix a burnt sender domain - Guarantee deliverability (no one can)
Step 1: Get Clear on What You Actually Need
Before you start trialing tools, nail down your real needs. Ask yourself:
- Are you sending at high volume? If you’re sending 100 emails a week, basic tools might suffice. If you’re blasting thousands, you need deeper insights and maybe automation.
- Do you need team features? Some tools are solo-only. Others let you collaborate or manage multiple sender identities.
- What’s your tech stack? If you’re using a basic ESP (Email Service Provider), you might need more help than if you’re on a platform built for outbound.
- What’s your budget? Don’t let pricing fool you—more expensive doesn’t mean better.
Pro tip: Write down your “must-haves” versus “nice-to-haves.” This keeps you from paying extra for stuff you’ll never use.
Step 2: Know What Features Actually Matter
Most deliverability tools pitch a laundry list of features. Here’s what’s worth caring about (and what’s not):
Must-Have Features
-
Inbox Placement Testing
This is why you’re here. The tool should send test emails to a network of real inboxes (Gmail, Outlook, Yahoo, etc.) and show you where they land. -
SPF/DKIM/DMARC Checks
These are the basics of email authentication. If you fail here, nothing else matters. -
Blacklist Monitoring
You want alerts if your sending domain or IP winds up on a major blacklist. -
Spam Filter Analysis
Good tools break down why your email might trip spam filters, not just if it did. -
Easy-to-Read Reports
Data is worthless if you can’t make sense of it. Look for tools that don’t bury the lead.
Nice-to-Have Features
-
Content Analysis
Some tools flag spammy words, weird formatting, or broken links. Useful, but don’t obsess. -
Preview on Different Clients
Handy if brand consistency is a must, but most B2B folks can live without pixel-perfect rendering. -
Automated Monitoring
If you’re sending major volumes over time, automated, ongoing checks can save you from surprises.
Features That Sound Good but Rarely Matter
-
“AI-powered” suggestions
Most of these are just basic keyword checks with a fancy name. -
Overly technical scoring systems
If you need a PhD to read the report, skip it. -
Integrations galore
Unless you’re managing at huge scale, you likely don’t need Slack, Zapier, and Salesforce hooks to check deliverability.
Step 3: Compare the Major Tools—Without the Hype
Let’s cut through the marketing and look at what’s out there. Here are the main players you’ll run into:
1. Mail-tester
What works:
Super simple. Send your test email to a provided address, get a clear 0–10 score with breakdowns for spamminess, blacklists, and authentication. Cheap (there’s a free tier, and paid plans are affordable). No login required for basic use.
What doesn’t:
Limited to one test at a time. No automation, no team features. Not the tool for high-volume, ongoing monitoring. But for small teams or early-stage, it’s often all you need.
2. GlockApps
What works:
Inbox placement testing across dozens of providers, ongoing monitoring, actionable reports. Handles both authentication and blacklist checks well.
What doesn’t:
Pricing can get high fast if you need automation or lots of tests. Interface is a bit dated. Occasional false positives.
3. MailReach
What works:
Targets cold emailers specifically. Offers inbox warming (which is a bit controversial—see below), decent reporting, and multi-inbox support. Good for teams.
What doesn’t:
Inbox “warming” is a gray area—some say it helps, others call it snake oil. Can get expensive. Not as strong on blacklist coverage.
4. SendForensics
What works:
Focuses on deliverability scoring and best practice audits. Clean reports, decent at flagging risky content.
What doesn’t:
Less about real-world inbox placement, more about “potential” issues. Not as focused on B2B outbound use cases.
5. Postmark Spam Check
What works:
Free, fast, and gives you a no-nonsense spam score. Great for quick checks.
What doesn’t:
Very limited—mainly a SpamAssassin analysis. Doesn’t check inbox placement or blacklists.
Pro tip: Don’t chase a perfect score. Real inboxes are messy, and even “10/10” emails can land in spam if your domain reputation is bad.
Step 4: Test Before You Buy
Most tools offer free trials or have a free tier. Don’t just trust reviews—run a few real tests.
- Send actual campaign emails, not dummy text.
- Try sending from different domains or subdomains if that’s your setup.
- See how easy it is to interpret the results.
- Check if the recommendations are things you can actually act on.
If you find yourself spending more time figuring out what the tool is telling you than fixing actual issues, move on.
Step 5: Watch Out for Common Pitfalls
-
Inbox “Warming” Hype:
Some tools promise to “warm up” your inbox by sending/receiving artificial emails. This can help a bit when starting with a new domain, but don’t expect miracles. ISPs are catching on, and overdoing it can look suspicious. -
Over-optimization:
Chasing a flawless score or obsessing over every flagged word is a waste of time. Focus on the big stuff: authentication, domain reputation, and sending habits. -
Ignoring the Real Problems:
All the testing in the world won’t fix a bad sender reputation, dirty list, or irrelevant content. If your open rates suck even after testing, time to look elsewhere.
Step 6: Make Your Pick and Set It Up
Once you’ve kicked the tires, pick the tool that:
- Gives you clear, actionable feedback
- Fits your actual workflow (not someone else’s)
- Doesn’t force you into a long contract or pay for features you’ll never use
Set up your core authentication (SPF, DKIM, DMARC). Run a baseline test before every major campaign. If you’re sending at scale, schedule regular checks.
Pro tip: Document what you fixed and what didn’t matter. This saves you (and your team) a ton of time down the line.
Keep It Simple—And Keep Iterating
Don’t let the perfect be the enemy of the good. Most B2B teams don’t need a $200/month deliverability suite. Start with something like Mail-tester, fix the obvious issues, and graduate to more advanced tools only if you hit real limits. Inbox placement is never 100% predictable, and anyone who says otherwise is selling you something.
Test, tweak, and move on. The real work is in sending relevant, wanted emails—not obsessing over every point on a spam score.