COMPARISON
zSender vs Mailgun
A developer email API + SMTP relay hosted in the EU, compared to Mailgun — on data residency, pricing, SMTP, and API.
The short version: Both zSender and Mailgun are transactional email platforms with a RESTful API, webhooks, and SMTP relay. Mailgun (a Sinch product) offers a selectable EU region, but it's opt-in — the US region is the default unless you choose the EU endpoint. zSender is hosted in Germany (Hetzner), so your recipients' email data is processed in the EU by default, with no region toggle to set or remember.
zSender vs Mailgun at a glance
| zSender | Mailgun | |
|---|---|---|
| Hosting region | Hosted in Germany (Hetzner) — your email data stays in the EU | US or EU region (you choose); EU region processes data in EU data centers |
| Free tier | 1,000 emails/month | 100 emails/day (forever-free) |
| Paid entry | $29/mo for 50,000 emails | Basic from $15/mo (10,000 emails) |
| SMTP relay | Yes — smtp.zsender.io (587/2525, STARTTLS) | Yes — SMTP relay supported |
| API | REST API + webhooks | RESTful API + webhooks |
| GDPR / data residency | GDPR-oriented; recipient email processed in the EU | EU region available for GDPR residency (opt-in); US is the default |
Mailgun details as of June 2026; verify current specifics on their site.
EU data residency: the core difference
Mailgun (a Sinch product) lets you choose a US or EU region; its EU region (api.eu.mailgun.net) processes data in EU data centers, but it is opt-in and the US region is the default unless you select the EU endpoint. zSender is EU-hosted by default, with no region to choose and no endpoint to remember — the email data path is in Germany from the first send.
Pricing compared
Mailgun's free plan allows about 100 emails/day, and its Basic plan starts at $15/mo for 10,000 emails. zSender's free tier is 1,000 emails/month and the single paid plan is $29/mo for 50,000 emails — a higher monthly send allowance once you're paying, on one flat plan.
SMTP relay and API
Both expose a RESTful API, webhooks, and an SMTP relay (Mailgun's is available even on the free plan). zSender's SMTP relay authenticates with your API key at smtp.zsender.io on ports 587/2525 (STARTTLS), so existing SMTP clients and libraries work without a rewrite.
Which should you choose?
Choose Mailgun if you want a selectable region and are comfortable configuring the EU endpoint yourself. Choose zSender if you'd rather EU residency be the default with nothing to toggle, and prefer a single simple plan over region-and-tier configuration.