Which Email Service Provider Should You Use in 2025? Postmark vs Mailgun
Email is a core communication channel we rely on at Hozuko, Singapore's direct-landlord property rental platform. We primarily send transactional emails, not marketing emails. This write-up evaluates email providers from that perspective.
Here are some popular options:
- Amazon Simple Email Service (Amazon SES)
- Postmark
- Resend
- SendGrid
- Mailgun
Initially, I assumed these services were more or less the same—so I didn’t think my choice would matter much.
- Amazon SES: Cheap and reportedly reliable. I’ve only used it briefly. I generally avoid Amazon tools due to their clunky UI/UX.
- Postmark: Frequently recommended on Reddit and tech blogs.
- SendGrid: I’ve used it before at Ninja Van, but I wanted to try something different.
- Resend: Founded in 2023. As a newer player, I was cautious—new companies often face growing pains that mature ones have already solved. That’s just a rule of thumb, of course.
- Mailgun: I picked it because an engineer I admire uses it. I assumed it’d be a safe bet.
Oh boy, was I wrong.
I had a horrible experience with Mailgun.
TL;DR: I had serious deliverability issues with Mailgun. Support took 2–3 weeks to respond, claimed they fixed the problem (they hadn’t), and pushed me to upgrade. I upgraded—still broken. I filed another ticket and waited again. Eventually, I switched to Postmark and had a flawless experience. Here’s what happened.
Comparing Postmark to Mailgun
Email Open Tracking
Before the deliverability issues, I encountered a peculiar problem with Mailgun’s open tracking: every email was marked as “opened” just one second after delivery.
Their response:
This can happen due to antivirus software, spam filters, or email clients that auto-open messages. We recommend using tags to view unique opens.
Fair enough. I implemented a workaround to ignore instant open events.
After switching to Postmark—no such issue.
IP Reputation
Checked via SenderScore:
- ✅ Postmark: 97
- ❌ Mailgun: 13
Postmark separates transactional IPs from bulk email pools. Mailgun doesn’t. I was repeatedly assigned low-reputation IPs that caused Microsoft to block my emails.
When I raised this with Mailgun, their excuse was:
There will always be risks associated with shared IPs... think of it like a highway: multiple drivers share the risk of its use, but still choose to use it in order to benefit.
I can’t justify using a dedicated IP—I don’t send enough volume, nor do I have the capacity to manage it.
Meanwhile, Postmark just worked.
Email Logs
- ✅ Postmark $15/mo plan: 45-day retention
- ❌ Mailgun $15/mo plan: 1-day retention
UI/UX
- ✅ Postmark: Clean, modern, and intuitive
- ❌ Mailgun: Dated and clunky
Customer Support
- ✅ Postmark: I haven’t needed support—because nothing has broken
- ❌ Mailgun: Slow, vague, and ultimately unhelpful
Conclusion
I can’t speak for every email provider—but I can confidently compare the two I’ve used.
❌ Don’t use Mailgun:
- Poor IP reputation = frequent deliverability issues (especially with Microsoft)
- Support is slow, indirect, and upsells without resolving issues
- Misleading communication
- Minimal log retention
- Outdated interface
- Wasted weeks of my time
✅ Use Postmark:
- Excellent deliverability
- Great IP reputation
- Better UI/UX
- No issues so far—everything just works
If you’re sending transactional emails in 2025, skip the frustration.
Go straight to Postmark.