A Courier alternative when you want the email, not the layer.

// Courier send over its REST API
const response = await fetch("https://api.courier.com/send", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.COURIER_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    message: {
      to: { email: "customer@example.com" },
      template: "RECEIPT_TEMPLATE_ID",
      data: { orderId: "48213" },
    },
  }),
});
// Courier then routes the message to the email provider you connected.

import { Notix } from "notix-js";

const notix = new Notix(process.env.NOTIX_API_KEY);

const { data, error } = await notix.emails.send(
  {
    from: "receipts@acme.com",
    to: "customer@example.com",
    templateId: "tpl_receipt_v4",
    variables: { orderId: "48213" },
  },
  { idempotencyKey: "order-48213-receipt" },
);
// Notix is the sender: no provider to connect, no routing layer between.

# Courier has no SMTP relay in its docs index; if your app already
# speaks SMTP, point it at Notix directly.
SMTP_HOST=smtp.usenotix.dev
SMTP_PORT=465          # or 587 for STARTTLS
SMTP_USER=notix
SMTP_PASS=<your Notix API key>