On Reddit there is no single best SMTP provider, but a handful of names come up far more than the rest. Across r/webdev and r/SaaS threads, Amazon SES is the default pick for developers who just want a cheap, reliable SMTP endpoint, Postmark is the service people trust most for deliverability, and a smaller group runs its own server with the open-source Postal project. SendGrid and Mailgun still get used, but they draw more complaints than praise.
What Reddit actually recommends
Amazon SES is the most common answer when the requirement is simply an SMTP endpoint that works. In one r/webdev thread on transactional email, an engineer put it plainly: it is cheap and reliable, and they do not need an interface, just SMTP. The catch users mention is that leaving the SES sandbox can involve approval questions, and a few report their SES IPs landing on blacklists.
Postmark gets repeated votes for speed and reliability on transactional mail, and users like that it keeps transactional and marketing streams separate. In a separate thread asking for a Mailgun alternative, the most upvoted replies were Resend, SES, and Postmark. SMTP2GO and Brevo also come up as solid options with usable free tiers for lower volume. For the hands-on crowd, a couple of users run postalserver/postal on their own IP with correct SPF, DKIM, and DNS, and report zero cost and no delivery problems after more than a year. That path only works if you are comfortable managing DNS and IP reputation yourself. If SMTP itself is new to you, our guide to what SMTP is covers the basics before you pick.
The caveats Redditors keep repeating
Almost every thread lands on the same point: the provider matters less than your sending practices. A well-configured domain on a mid-tier provider beats a sloppy setup on a premium one. Several users reported all of their shared IPs getting blacklisted regardless of which brand was on the invoice, which usually traces back to reputation and configuration rather than the provider itself. If you are weighing a hosted relay against running your own, our SMTP relay explainer lays out the tradeoffs, and the full transactional email services comparison goes deeper on pricing and deliverability per provider.
Whichever provider you settle on, keeping your email templates in your own tool rather than locked inside a provider makes switching painless. That is the gap Cold Letter fills: your templates and automations stay portable and work with any SMTP backend you send 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.