Turn incoming email into structured data

Point a domain’s MX records at Sendix and every message sent to it is parsed — headers, text, html and attachments — and handed to your app through a signed webhook and the receiving API.

Start sending free Read quickstart

MX on your own (sub)domain
email.received webhook
Forwarding rules
Reply through the API

email api request

ready

inbound-webhook.tsemail.received

import crypto from "node:crypto";

export async function POST(req: Request) {
  const raw = await req.text(); // verify before parsing
  const sig = Object.fromEntries(
    (req.headers.get("x-sendix-signature") ?? "")
      .split(",").map((part) => part.split("=")),
  );
  const expected = crypto
    .createHmac("sha256", process.env.SENDIX_WEBHOOK_SECRET!)
    .update(sig.t + "." + raw)
    .digest("hex");
  const fresh = Math.abs(Date.now() / 1000 - Number(sig.t)) < 300;
  const valid = fresh && sig.v1?.length === expected.length &&
    crypto.timingSafeEqual(Buffer.from(sig.v1), Buffer.from(expected));
  if (!valid) return new Response("invalid signature", { status: 401 });

  const event = JSON.parse(raw);
  if (event.type === "email.received") await routeInbound(event);
  return new Response("ok");
}

email.receivedX-Sendix-SignatureHMAC-SHA256

Short answer

How do I receive and parse inbound email with Sendix?

Enable receiving on a verified domain, publish the MX records Sendix shows, and subscribe a webhook to email.received. Each message is then available as parsed data through GET /v1/emails/receiving/{id} (attachments under /attachments), can be forwarded by rules created with POST /v1/emails/receiving/forwarding, and can be answered with POST /v1/emails/receiving/{id}/reply.

How it works

Four steps from app event to delivered email.

What your code does, what Sendix does, and where to look when something goes wrong.

01
POST /domains/{id}/receiving
Enable receiving
Turn on receiving for a verified domain — ideally a subdomain such as reply.acme.com.
02
DNS
Publish the MX records
Add the MX records from the domain page; Sendix checks them and reports receiving health.
03
webhooks
Subscribe to email.received
Create a webhook, verify X-Sendix-Signature on every delivery, then fetch the parsed message and attachments.
04
forwarding · reply
Route, forward or reply
Attach the message to a ticket or thread, forward it with a rule, or answer it through the reply endpoint.

Best practices

Details that keep this mail reliable.

Habits that protect deliverability and your users, whichever provider you use.

Use a subdomain for inbound

Receiving on reply.acme.com leaves the MX records of your main mailbox domain untouched.

Verify every webhook

Check the HMAC-SHA256 signature over t + "." + raw body in constant time and reject timestamps older than five minutes.

Thread with headers

Match replies to conversations with the Message-ID, In-Reply-To and References headers of the parsed message.

Process attachments asynchronously

Acknowledge the webhook quickly, then download attachments from the receiving API in a background job.

Make handlers idempotent

Webhook deliveries can be retried or replayed; store the event id before doing slow work.

Watch receiving health

GET /v1/emails/receiving/health shows whether inbound is configured and flowing for your domains.

Webhook events

The events worth subscribing to.

Sendix signs each webhook with X-Sendix-Signature and keeps the same events on the message at GET /v1/emails/{id}/events.

Event	What to do with it
email.received	What to do with itA message arrived on a receiving-enabled domain.

FAQ

Frequently asked questions

Short answers to the questions teams ask while wiring this up.

Do I have to move my whole domain’s email to Sendix?

No. Enable receiving on a subdomain (for example reply.acme.com) and publish MX records only there; mail to your main domain keeps flowing to your existing mailbox provider.