COMPARISON
zSender vs Resend
A developer email API + SMTP relay hosted in the EU, compared to Resend — on data residency, pricing, SMTP, and API.
The short version: Both zSender and Resend are developer-first email platforms with a REST API, webhooks, and SMTP support. Resend is US-based and offers an EU sending region, but account data is stored in the US; it also has a more generous free tier. zSender is hosted in Germany (Hetzner), so the full email data path — content, recipients, and logs — stays in the EU by default. The trade-off is usually free-tier size and headline price versus where your data physically lives.
zSender vs Resend at a glance
| zSender | Resend | |
|---|---|---|
| Hosting region | Hosted in Germany (Hetzner) — your email data stays in the EU | US-based; EU sending region available, but account data stored in the US |
| Free tier | 1,000 emails/month | 3,000 emails/month (100/day cap) |
| Paid entry | $29/mo for 50,000 emails | Pro $20/mo (50,000 emails) |
| SMTP relay | Yes — smtp.zsender.io (587/2525, STARTTLS) | Yes — SMTP supported |
| API | REST API + webhooks | REST API + webhooks |
| GDPR / data residency | GDPR-oriented; recipient email processed in the EU | US provider; no full EU-only data residency |
Resend details as of June 2026; verify current specifics on their site.
EU data residency: the core difference
Resend is a US-based provider. It offers an EU sending region (Dublin), but account data, logs, and metadata are stored in the US — so the full email data path is not EU-only. zSender runs in Germany, where recipient addresses, message content, and the delivery events we record are all processed and stored in the EU.
Pricing compared
Resend's free tier is more generous than ours — 3,000 emails/month (with a 100/day cap) versus zSender's 1,000/month — and its Pro plan is $20/mo for 50,000 emails versus zSender's $29/mo for the same volume. On headline price-per-email, Resend is cheaper; zSender's edge is where the data lives, not the sticker price.
SMTP relay and API
Both are developer-first, with a clean REST API, webhooks, and SMTP support, so the integration experience is comparable. The deciding factor between them is usually data residency rather than developer experience.
Which should you choose?
Choose Resend for the larger free tier and lower headline price if US-stored account data is acceptable for your use case. Choose zSender if you need the entire email data path — content, recipients, and logs — to stay in the EU, and you'll trade a slightly smaller free tier for that.