Mailgun is a genuinely good developer email API — clean docs, fast integration, real deliverability tooling. But every message still leaves from Mailgun's infrastructure and, on most plans, shared IP pools you don't control. mailstein runs the MTA on your own server, sends from your own IP, and bills you per send — not per contact.
Both platforms speak the same API and SMTP languages. The real divergence is whose reputation you're building — and who can throttle, suspend, or pool you when it matters.
Mailgun's cheaper plans send from shared IP pools where a stranger's spam run can dent your inbox placement. mailstein gives you a dedicated IP with managed warm-up — the reputation you earn is yours alone.
mailstein charges for emails you actually send. Store a million contacts, pay nothing extra until you email them. Transactional and broadcast run on the same meter — no separate marketing product to license.
Message logs, suppression lists, bounce and complaint data live in your own database — not behind a vendor's retention window. Full REST API, SMTP, webhooks, templates, audiences, and an MCP server for agents.
Mailgun does a lot well. Here's the honest breakdown of where the two platforms actually differ.
| mailstein | Mailgun | |
|---|---|---|
| Sends from your own server & IP | Yes | No — their infrastructure |
| Dedicated IP with managed warm-up | Included | Add-on, higher tiers |
| Shared IP pools by default | Never | Yes, on lower plans |
| Message logs stored on your infra | Yes | Vendor-side, retention limits |
| Transactional + broadcast, one platform | Yes, one meter | Broadcast is separate |
| Billing model | Per send | Per send |
| Automatic SPF / DKIM / DMARC setup | Yes | Yes |
| REST API + SMTP relay | Yes | Yes |
| SDK / CLI / MCP for agents | Yes | SDK only |
| Free tier | 50/mo + 1 domain, no card | Trial, then paid |
If you already send through Mailgun's API, you already know the pattern. Point your calls at mailstein, drop in your key, and your mail leaves from your own IP instead of a rented one. SMTP relay works too if you'd rather not touch code.
Start on the free tier — 50 emails a month and one domain, no card. Move real volume when you're ready, always billed per send.
Start free →