Mailblocks for Postmark

HTML email templates for Postmark.

Transactional email templates for Postmark: compiled HTML plus plain text for every message, React Email source when you want to customise.

Postmark rewards senders who include a real plain-text part. Every Mailblocks template ships with one, generated from the same source so the two never drift apart.

1
Render the template with @react-email/render (or read the pre-built file from dist/).
2
Send HtmlBody and TextBody together through the outbound transactional stream.
3
Optional: paste the HTML into a Postmark Template and swap values for {{mustache}} variables.

send.tsx

import { ServerClient } from "postmark";
import { render } from "@react-email/render";
import Receipt from "@/emails/receipt";

const postmark = new ServerClient(process.env.POSTMARK_SERVER_TOKEN!);
const email = <Receipt style="clean" amount="$158.40" receiptNumber="2418-7730" />;

await postmark.sendEmail({
  From: "billing@fieldnote.app",
  To: customer.email,
  Subject: "Your Fieldnote receipt [#2418-7730]",
  HtmlBody: await render(email),
  TextBody: await render(email, { plainText: true }),
  MessageStream: "outbound",
});

Keep billing and security mail on the transactional stream and digests/release notes on a broadcast stream.
Largest template is well under Gmail's 102 KB clipping limit, so Postmark's footer and unsubscribe links stay visible.
Postmark Templates use Mustachio: replace sample values in the HTML with {{variable}} placeholders.

Postmark docs: postmarkapp.com/developer/user-guide/send-email-with-api