Self-host MTA or buy SaaS? Lessons from 5 years of email ops
Postfix + Dovecot + Rspamd remain a worthwhile investment when you need granular rate limit control, audit logs, and cost efficiency at million-email-per-month scale. Real-world trade-offs.
When starting an email system, nearly every team faces the question: self-host MTA, or buy SendGrid / Mailgun / Postmark? After 5 years operating an email gateway processing millions of mails per month, here is our take.
When SaaS wins
If you send under 100K emails/month and don't need granular control over rate limits, IP warm-up, or real-time email content, SaaS is almost always cheaper and faster. Pay ~$10-$50/month and forget about DKIM, SPF, DMARC setup.
The problem arrives when you need programmatic email access: e.g. building disposable inboxes for signup testing, or a gateway that receives marketer emails and forwards to real users. At that point SaaS pricing breaks economics.
When self-hosting wins
Self-hosted Postfix + Dovecot + Rspamd trades complexity for total control: you decide spam policy, per-domain rate limits, log retention, header formats. Most importantly, no API call ceiling.
The big trade-off is operations: you need to understand DNS propagation, IP reputation, blacklist removal, MX failover. Expect 2-4 weeks of learning curve to ramp the team.
What HASoftware chose
We self-host because our product needs high email volume and deep customization. Each mailbox is created instantly via API, each message parsed and indexed in under a second. That's not something SaaS allows except at enterprise tier with custom contracts.
If you sit at the crossroads between options and want to discuss the trade-offs for your specific use case, drop us a line at [email protected].