Migrate from Postmark to Relayly

Why teams leave Postmark

No marketing tier. Postmark's broadcast/transactional split is intentional, but it forces a second tool for segments + automations.
Single region. Postmark is US-only. EU data residency requires moving.
Pricing climbs sharper than competitors. 10k sends = $15/mo, 50k = $50/mo, 300k = $200/mo. Relayly is $25/$25/$100 for the same.
Limited drag-drop editor. Postmark's templates are great for engineers, less so for non-technical marketers.

What carries across

Postmark concept	Relayly equivalent	Auto-migrates?
Servers	`Sub-accounts`	Yes — Scale tier and above. 1:1 mapping.
Message Streams	`Tagged sends + classification`	Streams become tag-based send classification on our side.
Templates (Mustache)	`Liquid templates`	Auto-translation handles the common cases.
Suppression list	`Suppressions`	Yes — bounces, spam complaints, unsubs.
Outbound API logs	`Read-only archive`	Optional. Search remains available for 90 days.
Inbound webhooks	`Inbound routes`	Yes — same parsed payload structure.

The codebase swap

API shapes are similar enough that find/replace handles most call sites. The key differences:

// Postmark Node SDK
import { ServerClient } from "postmark";
const client = new ServerClient(process.env.POSTMARK_TOKEN);

await client.sendEmail({
  From:     "hello@yourdomain.com",
  To:       "user@example.com",
  Subject:  "Welcome",
  HtmlBody: "<p>Hi</p>",
});

// Relayly Node SDK
import Relayly from "@relayly/node";
const r = new Relayly({ apiKey: process.env.RELAYLY_API_KEY });

await r.email.send({
  from:    { email: "hello@yourdomain.com" },
  to:      [{ email: "user@example.com" }],
  subject: "Welcome",
  html:    "<p>Hi</p>",
});

Message Streams → Tags

Postmark's Message Streams (transactional vs broadcast) split your account into distinct sending tracks. Relayly uses tags + auto-classification to achieve the same effect — sends with a broadcast tag automatically route through the marketing-grade IP pool, transactional sends through the priority pool.

The migrator transcribes your stream IDs to tag conventions. Most teams keep the same names: outbound, broadcast, marketing.

The cutover playbook

Run the export script. It's read-only against Postmark and re-runnable.
Review the manifest. Anything flagged as "needs review" gets a copy-paste remediation snippet.
Apply to Relayly. Idempotent SQL + REST imports. Re-run safely.
Dual-send for a week. Compare inbox rates at Gmail / O365 / Yahoo through the dashboard.
Flip the API key. Search-and-replace your codebase, deploy, monitor 24h.
Pause Postmark. Don't delete the account — keep it for 30 days as an unsubscribe-list reciprocity reference.
After 30 quiet days, terminate Postmark. You're done.

Pricing-side check

Volume	Postmark	Relayly	Annual delta
10k sends/mo	$15/mo	$25/mo	− $120/year
50k sends/mo	$50/mo	$25/mo	+ $300/year
300k sends/mo	$200/mo	$100/mo	+ $1,200/year
1M sends/mo + EU residency	Not available	$130/mo	EU residency unblocked

Postmark pricing as of 2026-05 from postmarkapp.com/pricing. Postmark is cheaper at the lowest tier; Relayly takes over from ~30k/mo and the gap widens at higher volume.

Start the migration

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