Send email from n8n

Two ways to send and one to receive. First: verify the domain in Couryo and create an API key with the send scope.

Send with the HTTP Request node (recommended)#

Through the API, each send returns the message ID and you can use an idempotency key: if the workflow runs again for the same item, the email does not go out twice.

1. Create a Header Auth credential (in Credentials > Add credential): name Authorization, value Bearer ck_live_....
2. Add an HTTP Request node:

3. In the body, use expressions with the previous node's data:

{
  "from": "Example Store <orders@example.com>",
  "to": "{{ $json.email }}",
  "subject": "Order {{ $json.order_id }} confirmed",
  "html": "<p>Hi {{ $json.name }}, we got your order.</p>",
  "text": "Hi {{ $json.name }}, we got your order.",
  "tags": { "source": "n8n" }
}

The 202 response carries { "id": "msg_...", "status": "queued" }. On error, the body carries error.code and error.message: turn on On Error > Continue (using error output) on the node to handle it in the workflow.

With a saved template, replace subject, html and text with "template": "order-confirmed" and "variables": { "name": "{{ $json.name }}" }.

Send with the Send Email node (SMTP)#

Create an SMTP credential:

On the Send Email node, the From Email must be on the verified domain.

Receive delivery events#

1. Add a Webhook node with method POST and copy the Production URL.
2. In the Couryo dashboard, under Webhooks, create a webhook with that URL and the events you care about (for example, bounced and complained). Keep the whsec_ secret.
3. Activate the workflow. Each event arrives with type and data (email_id, recipient, smtp_code, explanation...).

Check the signature#

To make sure the event came from Couryo, turn on the Raw Body option on the Webhook node and add a Code node right after it:

const crypto = require("crypto");

const secret = $env.COURYO_WEBHOOK_SECRET; // whsec_...
const headers = $input.first().json.headers;
const body = (await this.helpers.getBinaryDataBuffer(0, "data")).toString("utf8");

const key = Buffer.from(secret.replace(/^whsec_/, ""), "base64");
const expected = crypto
  .createHmac("sha256", key)
  .update(`${headers["webhook-id"]}.${headers["webhook-timestamp"]}.${body}`)
  .digest("base64");

const received = String(headers["webhook-signature"] || "").split(" ").map((s) => s.split(",")[1]);
const fresh = Math.abs(Date.now() / 1000 - Number(headers["webhook-timestamp"])) <= 300;
if (!fresh || !received.includes(expected)) throw new Error("invalid signature");

return [{ json: JSON.parse(body) }];

On self-hosted n8n, the crypto module must be allowed (NODE_FUNCTION_ALLOW_BUILTIN=crypto) and the COURYO_WEBHOOK_SECRET variable must exist in the environment. The full format is in Webhooks.

Workflow ideas#

• Order paid in your system → HTTP Request to Couryo with an Idempotency-Key equal to the order ID.
• bounced event → flag the contact in your CRM and tell the team in the sales channel.
• Sign-up event → POST https://api.couryo.com/v1/events with { "contact": { "email": ... }, "name": "user.signed_up" } to start a sequence.