If you go looking for a Mailgun vs SendGrid verdict on Reddit, the honest answer is that most experienced users have moved on from both. In r/webdev and r/vibecoding threads, people leaving Mailgun cite deliverability problems and pricing, while SendGrid draws complaints about support and account suspensions. The names that come up as replacements are almost always Amazon SES for cost, Resend for developer experience, and Postmark for deliverability.
What Redditors say about each
Sentiment on Mailgun has soured noticeably. In a thread on r/vibecoding weighing Mailgun, Resend, and Postmark, one user warned others not to touch Mailgun with a ten foot pole outside of the Ghost integration that forces it, and others describe deliverability issues plus pricing that feels steep as the reason they left. A few still run low-volume lists on the free plan without trouble, so it is not universally hated, but the enthusiasm is gone.
SendGrid gets called a safe middle ground by some, and plenty of users report no problems, but the recurring gripes are frustrating support and unexpected account suspensions that hit legitimate senders. In a thread about a high-volume signup flow, a developer said they were halfway through implementing SendGrid, then switched to Postmark after reading too many negative reviews. For a feature-by-feature look, our SendGrid vs Mailgun comparison breaks down where each one still makes sense.
What people switch to
The consensus migration path is consistent across threads. Redditors reach for Postmark when deliverability is the priority and they want zero headache, Amazon SES when they want the cheapest option and can handle more setup (in the Mailgun alternative thread, one user cut a monthly bill from around twenty dollars to a couple of dollars after moving to SES), and Resend when they want the fastest, cleanest developer onboarding. If Mailgun is what you are trying to replace, our Mailgun alternatives roundup and the Amazon SES vs SendGrid breakdown cover the same options in more detail.
One comment in these threads is worth repeating: own your email templates rather than locking them inside a provider, so switching costs stay low the next time deliverability or pricing pushes you to move. That portability is exactly what Cold Letter is built for, whichever provider you end up sending through.
I’ve spent my career building software at scale with a soft spot for email: deliverability, lifecycle campaigns, and getting messages to actually land. I started Coldletter to fix what bugged me about transactional and marketing email tools. I’m based in Vancouver.