Migrate

Migrate from Resend to AgenticEmail

How the API maps

import { Resend } from "resend";

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

await resend.emails.send({
  from: "support@yourdomain.com",
  to: "customer@example.com",
  subject: "Thanks for reaching out",
  html: "<p>Hi there - an agent will follow up shortly.</p>",
});

import { AgenticEmail } from "agenticemail";

const client = new AgenticEmail({ apiKey: process.env.AGENTICEMAIL_API_KEY });

// Create the inbox once, then reuse inbox.id (it also receives replies).
const inbox = await client.inboxes.create({ username: "support" });

await client.messages.send({
  inboxId: inbox.id,
  to: "customer@example.com",
  subject: "Thanks for reaching out",
  html: "<p>Hi there - an agent will follow up shortly.</p>",
});

// Resend posts inbound events for a configured domain.
app.post("/inbound", (req, res) => {
  const { from, subject, text } = req.body.data;
  res.sendStatus(200);
});

// Each inbox is a real address; inbound arrives as parsed JSON.
const { messages } = await client.messages.list({ inboxId: inbox.id });

for (const m of messages) {
  console.log(m.from, m.subject, m.text); // no MIME parsing required
}

// Or push instead of poll: register a signed webhook, or open the
// WebSocket stream at /v1/events for message.received events.

Migration steps

1. 1

   Install the SDK and set your key

   npm install agenticemail and set AGENTICEMAIL_API_KEY from the dashboard. Scope the key to specific inboxes for least-privilege per agent.

2. 2

   Create an inbox instead of a from address

   Where Resend sent from a verified domain, create an inbox with client.inboxes.create(). Omit the domain to use the shared sending domain, or add your own domain first.

3. 3

   Swap the send call

   Replace resend.emails.send(...) with client.messages.send({ inboxId, ... }). The to, subject, html, text, and attachment fields map directly, and batch sends carry over.

4. 4

   Add inbound and real-time

   Point a per-inbox webhook or the WebSocket stream at your handler, or poll client.messages.list(). Inbound is parsed JSON, scoped to the specific inbox.

5. 5

   Move your domain and cut over

   Add your domain; SPF, DKIM, and DMARC are generated and verified. Run traffic through both providers, compare, then flip fully.

What is different

• Resend is outbound-first. You are gaining a two-way inbox per agent, so restructure sends from a domain into sends from an inbox that also receives.
• Keep your React Email templates - render them to HTML and pass the result as `html`. AgenticEmail does not host templates for you.
• Resend's DX is a real strength; AgenticEmail matches the one-line send and type-safe SDK, and adds receiving, MCP, and end-to-end encryption on top.
• Cut over gradually: send through both providers, compare deliverability, then complete the switch.

Frequently asked questions

Is migrating from Resend hard?

No. The send call is nearly identical, and the SDK ergonomics are similar. The one change is sending from an inbox you create instead of a verified domain `from` - which is what gives you inbound replies, MCP, and end-to-end encryption.

Can I keep my domain and templates?

Yes to both. Add your domain and SPF, DKIM, and DMARC are generated and verified for you. Keep rendering your templates (React Email or otherwise) and pass the HTML to messages.send().

What do I gain over Resend?

A real, addressable inbox per agent that receives as well as sends, per-inbox webhooks and a WebSocket stream, a hosted MCP server so agents use email as a tool, and opt-in end-to-end encryption for agent-to-agent mail.

Can AgenticEmail still send transactional email like Resend?

Yes - transactional and conversational email with threading, attachments, and batch and scheduled sends. The same inboxes also receive and reply, which an outbound-only API does not.