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Migrating from Resend to Mailofly

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Key Benefits of Mailofly

• Multi-Identity Sending: Send from multiple brands, client sub-accounts, or environments using a single unified API key and lightweight account_key routing.
• Unified Audiences & Broadcasts: Manage transactional emails and rich visual marketing broadcasts under one roof—no need for separate third-party newsletter tools.
• Native AI MCP Server: Connect Mailofly directly to AI assistants (Cursor, Claude Desktop, Antigravity) via @mailofly/mcp.
• Zero Template Lock-in: Full support for React Email, standard HTML/CSS, and server-side mustache templates.

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1. Domain Setup & DNS

1. In the Mailofly dashboard, go to Domains → Add Domain.
2. Add the unique DNS records provided by Mailofly:
   • DKIM: Unique selector mailofly._domainkey.yourdomain.com (coexists with resend._domainkey).
   • SPF: Add include:mailofly.com to your domain’s SPF record. If you already have include:resend.com, you can temporarily keep both:
     v=spf1 include:resend.com include:mailofly.com ~all
     
3. Verify the domain in your dashboard.

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2. API & SDK Parameter Mapping

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3. Code Migration Examples

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Node.js / TypeScript

# Remove Resend
npm uninstall resend

# Install Mailofly
npm install @mailofly/node

import { Resend } from "resend";

const resend = new Resend(process.env.RESEND_API_KEY);

const data = await resend.emails.send({
  from: "Acme <hello@acme.com>",
  to: ["customer@example.com"],
  subject: "Welcome to Acme",
  html: "<p>Welcome aboard!</p>",
  tags: [
    { name: "category", value: "welcome" }
  ],
});

console.log("Resend Email ID:", data.id);

import { Mailofly } from "@mailofly/node";

const mailofly = new Mailofly({
  apiKey: process.env.MAILOFLY_API_KEY!,
});

const { id } = await mailofly.emails.send({
  from: "Acme <hello@acme.com>",
  to: ["customer@example.com"],
  subject: "Welcome to Acme",
  html: "<p>Welcome aboard!</p>",
  tags: [
    { name: "category", value: "welcome" }
  ],
  // Optional: specify a sending identity account key
  // account_key: process.env.MAILOFLY_ACCOUNT_KEY,
});

console.log("Mailofly Email ID:", id);

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Python

# Remove Resend
pip uninstall resend

# Install Mailofly
pip install mailofly

import resend
import os

resend.api_key = os.environ["RESEND_API_KEY"]

params = {
    "from": "Acme <hello@acme.com>",
    "to": ["customer@example.com"],
    "subject": "Welcome to Acme",
    "html": "<strong>Welcome!</strong>",
}

response = resend.Emails.send(params)
print("Resend ID:", response["id"])

from mailofly import Mailofly
import os

client = Mailofly(api_key=os.environ["MAILOFLY_API_KEY"])

response = client.emails.send(
    sender="Acme <hello@acme.com>",
    to=["customer@example.com"],
    subject="Welcome to Acme",
    html="<strong>Welcome!</strong>",
)

print("Mailofly ID:", response.id)

​

Raw HTTP / cURL

curl -X POST https://api.resend.com/emails \
  -H "Authorization: Bearer re_123456789" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "Acme <hello@acme.com>",
    "to": ["customer@example.com"],
    "subject": "Welcome",
    "html": "<p>Hello!</p>"
  }'

curl -X POST https://api.mailofly.com/emails \
  -H "Authorization: Bearer mf_live_xxxxxxxxxxxxxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "Acme <hello@acme.com>",
    "to": ["customer@example.com"],
    "subject": "Welcome",
    "html": "<p>Hello!</p>"
  }'

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4. React Email Support

import { Mailofly } from "@mailofly/node";
import { render } from "@react-email/render";
import { WelcomeEmail } from "./emails/WelcomeEmail";

const mailofly = new Mailofly({
  apiKey: process.env.MAILOFLY_API_KEY!,
});

// Render React Email to HTML
const emailHtml = await render(<WelcomeEmail name="Jane Doe" />);

const { id } = await mailofly.emails.send({
  from: "Acme <hello@acme.com>",
  to: ["jane@example.com"],
  subject: "Welcome to Acme!",
  html: emailHtml,
});

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5. Webhooks Migration

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Event Names Mapping

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Verifying Webhook Signatures in Next.js / Express

import { Webhook } from "svix";

export async function POST(req: Request) {
  const payload = await req.text();
  const svix_id = req.headers.get("svix-id");
  const svix_timestamp = req.headers.get("svix-timestamp");
  const svix_signature = req.headers.get("svix-signature");

  const wh = new Webhook(process.env.MAILOFLY_WEBHOOK_SECRET!);
  
  let evt;
  try {
    evt = wh.verify(payload, {
      "svix-id": svix_id!,
      "svix-timestamp": svix_timestamp!,
      "svix-signature": svix_signature!,
    }) as any;
  } catch (err) {
    return new Response("Invalid signature", { status: 400 });
  }

  const { type, data } = evt;

  switch (type) {
    case "email.delivered":
      console.log("Email delivered:", data.email_id);
      break;
    case "email.bounced":
      console.warn("Email bounced for:", data.to, "Reason:", data.bounce_reason);
      break;
  }

  return new Response("OK", { status: 200 });
}

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6. Audiences & Contacts Migration

1. Export from Resend:
   • Go to Resend Dashboard → Audiences.
   • Export your contact list to a .csv file.
2. Import into Mailofly:
   • Navigate to Audiences > Contacts.
   • Click Import CSV.
   • Map standard columns (email, first_name, last_name, unsubscribed) and any custom metadata properties.
   • Assign imported contacts to relevant Topics (e.g., Product Updates, Weekly Newsletter).

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Migration Checklist

• Add domain to Mailofly and configure DNS records (mailofly._domainkey).
• Verify SPF includes include:mailofly.com.
• Swap @mailofly/node (or mailofly Python package) in your codebase.
• Update environment variables with MAILOFLY_API_KEY.
• Point webhook endpoints to Mailofly Webhooks in the dashboard.
• Export and import contacts & suppressions into Mailofly.
• Remove legacy Resend SPF entries once 100% of traffic is switched.