PostStack vs Resend: Which Email API Should You Choose?

Resend is the benchmark for modern transactional email APIs — excellent developer experience, clean docs, a first-party React Email library. PostStack was built for teams who want the same DX but aren't ready to pay Resend's prices, and who care about EU data residency. Here's the honest breakdown.

Pricing at real volume

Resend's free tier is generous (3,000/month), but there's no paid tier below $20/month. The moment you cross 3,000 sends you jump straight to $20. PostStack starts paid plans at €5/month.

Monthly cost at common volumes:

3,000 emails: Resend $0 · PostStack €0
10,000 emails: Resend $20 · PostStack €5 — 75% cheaper
50,000 emails: Resend $20 · PostStack €15 — 25% cheaper
100,000 emails: Resend $90 · PostStack €65 — 28% cheaper
500,000 emails: Resend $450 · PostStack €325 — 28% cheaper
1,000,000 emails: Resend $900 · PostStack €650 — 28% cheaper

Where Resend is genuinely better

Resend's React Email integration is first-party and very polished. If your entire email design stack is already built on React components, that workflow is smoother than any templating system. Resend also has a slightly larger community and more third-party content on the open web.

Where PostStack is better

IMAP/POP3 mailboxes — PostStack ships real mailboxes with Dovecot so your @yourdomain.com addresses can send and receive like Google Workspace. Resend doesn't do mailboxes at all.
Visual email builder — drag-and-drop block-based editor included in the dashboard. Resend leaves you to build your own.
DMARC aggregate reports — PostStack parses and surfaces DMARC reports automatically. Resend doesn't support this.
Workflow automation — multi-step automations with delays and branches. Resend's audience features stop at broadcasts.
Embeddable signup forms — drop a form on any site and collect contacts straight into PostStack.
EU data residency — PostStack is EU-hosted (Germany + Finland) and built under GDPR. Resend is a US company running on US infrastructure.
Dedicated IP on the Scale plan, not gated behind "contact sales".

Developer experience

Both APIs have a similar shape. PostStack was designed with Resend's conventions in mind so migration is near-trivial. A send call looks almost identical:

// Resend
await resend.emails.send({
  from: 'hello@yourdomain.com',
  to: 'user@example.com',
  subject: 'Hello!',
  html: '<h1>Welcome!</h1>',
});

// PostStack
await poststack.emails.send({
  from: 'hello@yourdomain.com',
  to: 'user@example.com',
  subject: 'Hello!',
  html: '<h1>Welcome!</h1>',
});

Both ship TypeScript SDKs and webhook payloads with the same event vocabulary (delivered, bounced, opened, clicked, complained).

When to pick each

Pick Resend if you're all-in on React Email, you're a US-based team without EU data concerns, and the extra $15/month at 10,000 sends isn't a factor.

Pick PostStack if you want the same clean API at a fraction of the cost, EU data residency, real mailboxes, and features like DMARC reporting and workflow automation without paying enterprise prices.

Migrating from Resend

If you're already on Resend the migration is about an hour's work — the SDK is a drop-in replacement. See the Resend migration guide for the exact steps, or start on the free plan and try PostStack side-by-side.