Mailchimp Transactional

The Mailchimp adapter calls the Mailchimp Transactional API, the API formerly known as Mandrill, with plain fetch. Unusually, the API key travels in the request body rather than a header, and recipients are a single typed list (to/cc/bcc entries) instead of separate arrays.

Mailchimp Transactional

@opencoredev/email-sdk/mailchimp

OfficialNot API testedRequest tested

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Configure

Create a Transactional API key in the Mandrill dashboard (Settings → SMTP & API Info) and verify your sending domain.

import { createEmailClient } from "@opencoredev/email-sdk";
import { mailchimp } from "@opencoredev/email-sdk/mailchimp";

export const email = createEmailClient({
  adapters: [mailchimp({ apiKey: process.env.MAILCHIMP_API_KEY! })],
});

Send

Mailchimp maps cc, bcc, headers, attachments, tags (values only), and metadata. sendAt maps to Mailchimp's send_at (a UTC timestamp), and Mailchimp only schedules email for accounts with a positive balance.

const result = await email.send({
  from: "Acme <hello@acme.com>",
  to: [{ email: "user@example.com", name: "Ada" }],
  subject: "Your order has shipped",
  html: "<p>Order ord_123 is on its way.</p>",
  metadata: { orderId: "ord_123" },
  tags: [{ name: "type", value: "shipping" }],
});

console.log(result.id); // Mandrill _id of the first recipient result

Mandrill responds with one result per recipient; the normalized id and messageId come from the first result's _id. Each result also carries a per-recipient status (sent, queued, rejected). If a send succeeds but mail does not arrive, check result.raw during smoke tests, because a rejected status still counts as a successful API call.

Verify from the CLI

MAILCHIMP_API_KEY="md-..." npx email-sdk doctor --adapter mailchimp

MAILCHIMP_API_KEY="md-..." npx email-sdk send \
  --adapter mailchimp \
  --from "Acme <hello@acme.com>" \
  --to user@example.com \
  --subject "Mailchimp smoke test" \
  --text "It works" \
  --dry-run

Drop --dry-run for one real send and check the per-recipient status in the output; Mandrill can accept the request and still reject the recipient.