If you run B2B email campaigns, you probably know the drill: send, hope for the best, then spend too much time wondering why your emails landed in spam or never got opened. There are dozens of tools promising to fix your deliverability woes, but most don’t explain what’s actually happening—or what’s worth your time.
This guide cuts through the noise. If you’re deciding between Mail-tester and its main competitors, or just want to know which tools actually help B2B teams get into inboxes (instead of spam folders), you’re in the right place.
Why Deliverability Tools Matter (But Won’t Do Everything)
Let’s be honest: most email deliverability tools won’t magically get your emails into inboxes. What they do well is help you spot obvious problems—bad technical setups, spammy content, or blacklists you didn’t know about.
But don’t expect miracles. If your email list is old or you’re sending generic, salesy stuff to cold prospects, no tool is going to save you. Instead, use these tools to fix things you can control: technical setup, content, and sender reputation.
Quick Overview: What Is Mail-tester?
Mail-tester is a straightforward web tool: you send an email to a random address they give you, and it spits out a score (out of 10) along with a checklist of what’s wrong—SPF, DKIM, blacklists, and spammy content.
No account, no fancy dashboards, no upsells. It’s simple, fast, and cheap. For solo marketers or small teams, it’s often enough.
The Main Competitors (And What They Actually Do)
Let’s size up Mail-tester against the usual suspects:
- GlockApps: More advanced, simulates inbox placement at different providers, tests for authentication, spam content, and blacklists.
- Mailtrap: Geared towards developers and QA; tests staging/transactional emails, not really for live marketing campaigns.
- Litmus: Expensive, focused on design previews and rendering across devices and clients, not pure deliverability.
- SendForensics: Deep-dive scoring, reputation tracking, and deliverability analytics, with more ongoing monitoring.
- MXToolbox: Toolbox for technical checks—DNS, blacklists, authentication—but not tailored for marketers.
- SpamAssassin: Open-source spam filter used by many providers, but not a “tool” in itself for marketers; more technical.
Side-by-Side: What Matters for B2B Campaigns
Here’s where the rubber meets the road. You don’t need every feature—just the ones that help you land in real business inboxes.
| Feature | Mail-tester | GlockApps | Mailtrap | Litmus | SendForensics | MXToolbox | |-----------------|-------------|--------------|---------------|-------------|---------------|-------------| | Spam score | ✔️ | ✔️ | ✔️ (dev focus) | ✔️ (some) | ✔️ | ❌ | | Inbox preview | ❌ | ✔️ | ❌ | ✔️ | ❌ | ❌ | | Blacklist check | ✔️ | ✔️ | ❌ | ❌ | ✔️ | ✔️ | | Auth check | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | ✔️ | | Ongoing monitor | ❌ | ✔️ | ✔️ (dev/test) | ✔️ | ✔️ | ✔️ | | Price | Low | Medium/High | Medium | High | Medium/High | Free/$ | | Ease of use | Simple | Moderate | Dev-centric | Complex | Moderate | Technical |
Honest take:
- Mail-tester nails the basics, fast and cheap, but it’s a one-off tool—not for big teams or ongoing monitoring.
- GlockApps is great for serious campaigns or agencies, but pricey for solo use.
- Mailtrap is great if you’re testing transactional emails in dev, not for marketing.
- Litmus is overkill if you just care about deliverability, but a lifesaver if you obsess over how things look on every device.
- SendForensics is for those who want deep analytics and don’t mind paying or learning new dashboards.
- MXToolbox is a lifesaver for DNS and blacklist headaches but isn’t “marketer-friendly.”
Real-World Use: When Each Tool Actually Helps
1. You’re sending cold B2B campaigns and just want to avoid spam
- Mail-tester: Send a test email, fix the red flags (SPF, DKIM, spam words, blacklists). That’s 80% of the value for most folks.
- Skip the expensive previews or analytics—your cold prospects mostly use Outlook or Gmail, not 15 different clients.
2. You’re an agency running campaigns for multiple clients
- GlockApps: Worth the money if you need to show clients actual inbox placement at different providers and want ongoing alerts.
- SendForensics: Good for tracking long-term reputation and campaign health.
- Mail-tester: Still handy as a quick preflight check.
3. You’re a developer or product team testing transactional emails
- Mailtrap: Excellent for testing in staging without sending real emails. Not for bulk marketing.
- MXToolbox: Useful for debugging DNS and SMTP issues.
4. You care about pixel-perfect design
- Litmus: The gold standard for checking what your email looks like everywhere. But if your B2B contacts open in Outlook 2016 and Gmail, you might not need all the bells and whistles.
What Actually Moves the Needle in B2B Deliverability
Here’s a quick reality check:
- SPF, DKIM, and DMARC: If you’re missing any of these, fix it now. All the tools above check them, but you can also use free DNS checkers.
- Content: Avoid spammy phrases, weird formatting, and attachments. Mail-tester and GlockApps flag these.
- Blacklists: If your sending IP/domain is on a blacklist, get off it or change providers. Mail-tester, GlockApps, SendForensics, and MXToolbox all help here.
- List quality: No tool will fix a list full of cold, scraped, or purchased emails. Clean your list and stop sending to people who never open.
- Sending practices: Warm up new domains, don’t blast thousands of emails from a fresh address, and watch your bounce rates.
Pro tip:
Don’t get obsessed with hitting a “10/10” spam score. Sometimes a 7 or 8 is fine—real-world engagement matters more. Focus on sending relevant stuff to people who actually want it.
What to Ignore (Or Not Pay Extra For)
- Dozens of design previews: Unless your B2B list is super diverse, you probably don’t need to see how your email looks in 20 apps no one uses.
- Deep analytics dashboards: If you’re not going to act on the data, don’t pay for it.
- Ongoing monitoring for small lists: If you’re only sending a few campaigns a month, a quick Mail-tester check is often enough.
How To: A Simple B2B Email Deliverability Checklist
-
Set up SPF, DKIM, and DMARC.
Use a tool—any tool, really—to confirm they’re valid. MXToolbox or Mail-tester both work. -
Send a test campaign to Mail-tester.
Fix any issues it flags—especially blacklists and spammy content. -
Warm up your sending domain.
Don’t send 1,000 emails from a brand new address. Start slow. -
Clean your list.
Remove old, invalid, or disengaged addresses. No tool will do this for you. -
Check your sending reputation.
Use GlockApps or SendForensics if you want ongoing data, but don’t overthink it if you’re a small sender. -
Track real responses.
Focus on replies, opens, and clicks. Deliverability scores are a means, not the end.
Bottom Line: Keep It Simple, Focus on What Works
You don’t need a wall of dashboards or a $200/month subscription to get decent B2B deliverability. For most teams, Mail-tester is a quick, no-nonsense gut check. If you run more complex campaigns or need to impress clients, GlockApps or SendForensics might be worth it.
But the basics still matter most: technical setup, clean lists, and relevant content. Start there, keep it simple, and iterate as you grow. Don’t let tool FOMO distract you from what really lands you in the inbox.