SendGrid clone

Test SendGrid mail/send and dynamic template rendering against a stateful email twin — captured messages land in an in-memory inbox with bounce and spam-trap simulation. No delivery to the real internet.

Clone ID: sendgrid (registry) · Runtime kind: email · Binary: clones-email · SDK: email

The catalog lists sendgrid; spawn and SDK calls use kind: "email". The same binary also serves Resend and SMTP capture — see Email clone for the full multi-provider surface.

Start here

Question	Answer
Best for	Transactional mail via `POST /v3/mail/send`, dynamic template data, and deliverability edge cases
Connect with	SendGrid SDK with base URL override, route mode for `api.sendgrid.com`, REST at `{base}/t/{runId}/v3/...`, or MCP inbox tools
Known limits	Deep clone implements `POST /v3/mail/send` only; marketing stats/templates are fixture-tier responses when using the fixture server
Seeds	Empty by default; seed domains via admin JSON or create over REST

MCP tools

Tool	Description
`molar_clone_spawn`	Spawn email clone (`kind: "email"`, optional `seed`)
`email_inbox`	Read captured messages for a recipient
`email_mark_bounce`	Mark recipient as hard-bounced
`molar_clone_advance_clock`	Advance virtual time (domain verification, delivery timing)

REST API coverage

Deep clone (Go engine)

Stateful SendGrid-compatible REST at {base}/t/{runId}/v3/...:

POST /v3/mail/send — send with dynamic_template_data rendering; messages captured in inbox

Fixture tier (recorded responses)

When using the fixture server path {base}/sendgrid/api/...:

POST /v3/mail/send
GET /v3/stats
GET /v3/templates, GET /v3/templates/{id}, PUT /v3/templates/{id}
GET /v3/marketing/contacts, /v3/marketing/lists, /v3/marketing/senders

Use the deep clone for inbox capture and clock-driven delivery. Use fixtures when you only need static marketing API shapes.

Seeds and initial state

Approach	Detail
Empty	Default — no verified domains
Admin JSON	`POST /_clone/seed` with `{ "domains": [{ "name": "example.com" }] }`
Fixture seed	`empty` (fixture tier only)

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

const clone = await email.start({ runId: "run-sendgrid-01" });
await clone.adminPost(`/_clone/seed?runId=${clone.runId}`, {
  domains: [{ name: "example.com" }],
});

Connect

Mode	URL pattern
Deep REST	`{clone.url}/t/{runId}/v3/mail/send`
Route mode	Map `api.sendgrid.com` via `molar_clone_route`
SMTP	Port `1025` on the email binary (same inbox)
Dashboard	Clones explorer

Authorization: use the derived test API key from the SDK spawn response.

See Email clone for Resend, SMTP, and cross-clone receipt flows.

Email Auth (Clerk)