Keep your Resend code. Change one line.

import { Resend } from "resend";

const resend = new Resend(
  process.env.SPACEPOST_API_KEY,
  { baseUrl: "https://api.spacepost.dev" },
);

const { data, error } = await resend.emails.send({
  from: "Acme <onboarding@test.spacepost.dev>",
  to: ["delivered@test.spacepost.dev"],
  subject: "Hello from SpacePost",
  html: "<p>It works.</p>",
});

import { Resend } from "resend";

const resend = new Resend(
  process.env.RESEND_API_KEY,
  { baseUrl: "https://api.resend.com" },
);

const { data, error } = await resend.emails.send({
  from: "Acme <onboarding@test.spacepost.dev>",
  to: ["delivered@test.spacepost.dev"],
  subject: "Hello from SpacePost",
  html: "<p>It works.</p>",
});

→{ data: { id: "0192f3a4-7c1e-7b6d-9a35-2f0e6f1d8c10" }, error: null }

// npm install @spacepost/node
import { SpacePost } from "@spacepost/node";

const spacepost = new SpacePost(process.env.SPACEPOST_API_KEY);

const { data, error } = await spacepost.emails.send({
  from: "Acme <onboarding@test.spacepost.dev>",
  to: ["delivered@test.spacepost.dev"],
  subject: "Hello from SpacePost",
  html: "<p>It works.</p>",
});

→{ data: { id: "0192f3a4-7c1e-7b6d-9a35-2f0e6f1d8c10" }, error: null }

curl -X POST https://api.spacepost.dev/emails \
  -H "Authorization: Bearer $SPACEPOST_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "Acme <onboarding@test.spacepost.dev>",
    "to": ["delivered@test.spacepost.dev"],
    "subject": "Hello from SpacePost",
    "html": "<p>It works.</p>"
  }'

→{"id":"0192f3a4-7c1e-7b6d-9a35-2f0e6f1d8c10"}

import nodemailer from "nodemailer";

const smtp = nodemailer.createTransport({
  host: "smtp.spacepost.dev",
  port: 25976,
  requireTLS: true, // STARTTLS
  auth: { user: "spacepost", pass: process.env.SPACEPOST_API_KEY },
});

await smtp.sendMail({
  from: "Acme <onboarding@test.spacepost.dev>",
  to: "delivered@test.spacepost.dev",
  subject: "Hello from SpacePost",
  html: "<p>It works.</p>",
});

→250 OK: queued as 0192f3a4-7c1e-7b6d-9a35-2f0e6f1d8c10

# Claude Code: add the hosted MCP server
claude mcp add --transport http spacepost https://api.spacepost.dev/mcp \
  --header "Authorization: Bearer $SPACEPOST_API_KEY"

# Or run it locally over stdio
claude mcp add spacepost -e SPACEPOST_API_KEY=$SPACEPOST_API_KEY \
  -- npx -y @spacepost/mcp