Resend

The Resend adapter calls the Resend Email API directly. It does not add a runtime dependency.

Resend

@opencoredev/email-sdk/resend

OfficialNot API testedRequest tested

Before live sends

Create a Resend API key and verify the sender domain or sender address you plan to use in from. A dry run can validate the Email SDK message shape, but only a live send from your target environment proves the Resend account, sender, and recipient policy are ready.

Configure

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

const email = createEmailClient({
  adapters: [resend({ apiKey: process.env.RESEND_API_KEY! })],
});

Send

const result = await email.send(
  {
    from: "Acme <hello@acme.com>",
    to: [{ email: "user@example.com", name: "Ada" }],
    cc: "billing@example.com",
    replyTo: "support@example.com",
    subject: "Welcome",
    html: "<p>Your workspace is ready.</p>",
    headers: {
      "X-Template": "welcome",
    },
    tags: [{ name: "type", value: "welcome" }],
    attachments: [
      {
        filename: "welcome.txt",
        content: "Welcome to Acme.",
        contentType: "text/plain",
      },
    ],
  },
  {
    idempotencyKey: "welcome:user_123",
  },
);

console.log(result.provider, result.messageId);

Resend supports attachments and tags, but it does not support Email SDK metadata. If metadata matters for routing or analytics, choose another fallback route.

Options

Option	Type	Required	Notes
`apiKey`	`string`	Yes	Resend API key.
`baseUrl`	`string`	No	Defaults to `https://api.resend.com`.
`fetch`	`typeof fetch`	No	Useful for tests or custom runtimes.
`headers`	`Record<string, string>`	No	Extra request headers.

Response

The adapter returns the Resend id as id and messageId.

CLI smoke test

RESEND_API_KEY="re_..." npx email-sdk send \
  --adapter resend \
  --from "Acme <hello@acme.com>" \
  --to user@example.com \
  --subject "Resend test" \
  --text "It works"