Email clone

Capture outbound email across Resend, SendGrid v3, and SMTP in one clone — inspect inboxes, simulate bounces and spam traps, and advance the virtual clock for domain verification and delivery.

Clone ID: email · Binary: clones-email · SDK: email · Registry alias: sendgrid · Dashboard: Email explorer

Start here

Question	Answer
Best for	Welcome emails, password reset, receipts, SendGrid dynamic templates, and bounce paths
Connect with	Resend/SendGrid SDK pointed at clone URL, route mode for `api.sendgrid.com` / `api.resend.com`, SMTP to port `1025`, or MCP inbox tools
Known limits	No delivery to the real internet — all messages stay in the clone
Seeds	Empty by default; seed domains via JSON or create them over REST

Quick start

import { email } from "@molar/clones";

const clone = await email.start({ seed: "welcome-flow", runId: "run-email-01" });

await clone.send({
  from: "hello@example.com",
  to: ["user@example.com"],
  subject: "Welcome to Pro",
  html: "<p>Thanks!</p>",
});

await clone.advanceClock("5s");
const messages = await clone.inbox("user@example.com");

MCP tools

Tool	Description
`molar_clone_spawn`	Spawn Email clone (`kind: "email"`, optional `seed`)
`email_inbox`	Read captured messages for a recipient (`adminUrl`, `runId`, `recipient`)
`email_mark_bounce`	Mark recipient as hard-bounced for deliverability tests

REST API coverage

Provider shape	Endpoints
Resend	`POST /emails`, `POST /emails/batch`, `GET /emails`, `GET /emails/:id`
Resend domains	`POST /domains`, list/get/delete; status moves to `verified` on clock advance
Resend audiences	`POST /audiences`, `POST /audiences/:id/contacts`
SendGrid v3	`POST /v3/mail/send` with `dynamic_template_data` rendering
SMTP	Mailpit-compatible capture on `127.0.0.1:1025` (raw messages land in the same inbox)
Mailpit-compat	`GET /api/v1/messages`, `POST /api/v1/chaos`
Admin	Inbox list, bounce/spam-trap flags

Set RESEND_API_KEY or SendGrid key to the derived test key from the SDK spawn response.

Seeds and initial state

There is no bundled welcome seed. Typical patterns:

// Seed a verified domain via admin JSON
await clone.adminPost(`/_clone/seed?runId=${clone.runId}`, {
  domains: [{ name: "example.com" }],
});

// Or create via REST
await clone.request("/domains", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({ name: "example.com" }),
});
await clone.advanceClock("1m");

Dashboard preset Checkout Stripe + Receipt pairs stripe + email for payment confirmation mail.

Limits

Limit	Detail
Attachments	In-memory per message
Multi-recipient	Supported; inbox keyed by `to` address
Delivery timing	Advance clock after send to reach `delivered`
Cross-clone	Checkout receipt (`stripe` + `email`), password reset (`auth` + `email`) — Scenarios

Inbox & bounce

await clone.markBounce("bad@example.com");
await clone.markSpamTrap("trap@spam.org");
const inbox = await clone.inbox("user@example.com");

Environment variables

MOLAR_CLONE_EMAIL_URL, MOLAR_CLONE_EMAIL_ADMIN_URL, RESEND_API_KEY (derived test key)

Twilio SendGrid