Send Campaign

Send a campaign immediately, or schedule it for future delivery. To send now, omit the body (or send an empty object). To schedule, include a scheduled_at ISO 8601 datetime in the future.

The campaign must be in Draft or Scheduled status with all required fields configured: sender address, subject, email content (via a template), and at least one recipient list or tag.

Endpoint

POST /email/campaigns/:id/send

Returns: 200 OK

Path Parameters

Parameter	Type	Required	Description
id	string	Yes	The campaign ID.

Headers

Header	Value	Required
Authorization	Bearer <your-api-key>	Yes
Content-Type	application/json	When sending a body
Idempotency-Key	Any unique string, max 256 chars	No — makes a retry safe; see Idempotency

Body Parameters

Parameter	Type	Required	Description
scheduled_at	string	No	ISO 8601 datetime in the future. Omit to send immediately.

Send vs. Schedule

• Omit scheduled_at — the campaign moves to Queued and starts sending right away.
• Include scheduled_at — the campaign moves to Scheduled and will start sending at that time. You can change the scheduled time by calling this endpoint again with a new scheduled_at, or cancel the campaign before it sends.

Response

{
  "id": "0192a1b2-c3d4-7e5f-9000-abcdef123456"
}

tip

The campaign is queued, not yet delivered. Use GET /email/campaigns/:id to poll the campaign status as it progresses through Queued → Sending → Sent.

---

Unsubscribe Compliance

Every marketing campaign must give recipients a way to opt out. Arsel enforces this automatically using the reserved variable {{unsubscribe_link}}.

How it works

At send time, {{unsubscribe_link}} in your template HTML is replaced per-recipient with a unique tracked unsubscribe URL. Clicking it unsubscribes the contact and updates your suppression list immediately. A List-Unsubscribe header is also added to every outgoing message so inbox providers (Gmail, Outlook, Apple Mail) can surface their built-in unsubscribe button.

If your template has no unsubscribe element, Arsel automatically appends a minimal footer containing the unsubscribe link before sending. The campaign is never rejected for a missing token — you get the footer for free.

<!-- Recommended: place this wherever you want the link in your template -->
<a href="{{unsubscribe_link}}">Unsubscribe</a>

<!-- If omitted entirely, this footer is appended automatically -->
<div style="text-align:center;padding:16px 0;font-size:12px;color:#888888;font-family:Arial,sans-serif;">
  <a href="{{unsubscribe_link}}">Unsubscribe</a>
</div>

Legacy syntax

Templates containing [%unsubscribe_link%] (the older Stripo/SES format) are automatically normalized to {{unsubscribe_link}} during sending. Both forms work.

Custom unsubscribe URLs are not supported

If your template contains an anchor whose visible text says "Unsubscribe" and whose href is a real external URL (not {{unsubscribe_link}}), the send request is rejected with 400 bad_request. Custom URLs bypass the suppression list and break compliance tracking.

{
  "status_code": 400,
  "name": "bad_request",
  "message": "Your template contains a custom unsubscribe URL. Replace it with {{unsubscribe_link}} to ensure compliance tracking."
}

Replace the custom href with {{unsubscribe_link}} and re-send.

---

Examples

Send Now

cURL

curl -X POST "https://api.arsel.sa/v1/email/campaigns/0192a1b2-c3d4-7e5f-9000-abcdef123456/send" \
  -H "Authorization: Bearer $ARSEL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{}'

JavaScript

const response = await fetch("https://api.arsel.sa/v1/email/campaigns/0192a1b2-c3d4-7e5f-9000-abcdef123456/send", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.ARSEL_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({}),
});

const data = await response.json();
if (!response.ok) {
  throw new Error(`${data.name}: ${data.message}`);
}

console.log(data);

Python

import os

import requests

response = requests.post(
    "https://api.arsel.sa/v1/email/campaigns/0192a1b2-c3d4-7e5f-9000-abcdef123456/send",
    headers={"Authorization": f"Bearer {os.environ['ARSEL_API_KEY']}"},
    json={},
)
response.raise_for_status()

print(response.json())

C#

using System.Net.Http.Headers;
using System.Text;

var client = new HttpClient(); // share one instance across requests
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(
    "Bearer", Environment.GetEnvironmentVariable("ARSEL_API_KEY"));

var request = new HttpRequestMessage(HttpMethod.Post, "https://api.arsel.sa/v1/email/campaigns/0192a1b2-c3d4-7e5f-9000-abcdef123456/send")
{
    Content = new StringContent(
        """
        {}
        """,
        Encoding.UTF8,
        "application/json"),
};

var response = await client.SendAsync(request);
var body = await response.Content.ReadAsStringAsync();
if (!response.IsSuccessStatusCode)
    throw new HttpRequestException($"{(int)response.StatusCode}: {body}");

Console.WriteLine(body);

PHP

<?php
$ch = curl_init("https://api.arsel.sa/v1/email/campaigns/0192a1b2-c3d4-7e5f-9000-abcdef123456/send");
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_CUSTOMREQUEST => "POST",
    CURLOPT_HTTPHEADER => [
        "Authorization: Bearer " . getenv("ARSEL_API_KEY"),
        "Content-Type: application/json",
    ],
    CURLOPT_POSTFIELDS => "{}",
]);

$data = json_decode(curl_exec($ch), true);
if (curl_getinfo($ch, CURLINFO_HTTP_CODE) >= 400) {
    throw new Exception("{$data['name']}: {$data['message']}");
}

print_r($data);

Schedule for Later

cURL

curl -X POST "https://api.arsel.sa/v1/email/campaigns/0192a1b2-c3d4-7e5f-9000-abcdef123456/send" \
  -H "Authorization: Bearer $ARSEL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "scheduled_at": "2026-05-01T09:00:00Z"
  }'

JavaScript

const response = await fetch("https://api.arsel.sa/v1/email/campaigns/0192a1b2-c3d4-7e5f-9000-abcdef123456/send", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.ARSEL_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    scheduled_at: "2026-05-01T09:00:00Z",
  }),
});

const data = await response.json();
if (!response.ok) {
  throw new Error(`${data.name}: ${data.message}`);
}

console.log(data);

Python

import os

import requests

response = requests.post(
    "https://api.arsel.sa/v1/email/campaigns/0192a1b2-c3d4-7e5f-9000-abcdef123456/send",
    headers={"Authorization": f"Bearer {os.environ['ARSEL_API_KEY']}"},
    json={
        "scheduled_at": "2026-05-01T09:00:00Z",
    },
)
response.raise_for_status()

print(response.json())

C#

using System.Net.Http.Headers;
using System.Text;

var client = new HttpClient(); // share one instance across requests
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(
    "Bearer", Environment.GetEnvironmentVariable("ARSEL_API_KEY"));

var request = new HttpRequestMessage(HttpMethod.Post, "https://api.arsel.sa/v1/email/campaigns/0192a1b2-c3d4-7e5f-9000-abcdef123456/send")
{
    Content = new StringContent(
        """
        {
          "scheduled_at": "2026-05-01T09:00:00Z"
        }
        """,
        Encoding.UTF8,
        "application/json"),
};

var response = await client.SendAsync(request);
var body = await response.Content.ReadAsStringAsync();
if (!response.IsSuccessStatusCode)
    throw new HttpRequestException($"{(int)response.StatusCode}: {body}");

Console.WriteLine(body);

PHP

<?php
$ch = curl_init("https://api.arsel.sa/v1/email/campaigns/0192a1b2-c3d4-7e5f-9000-abcdef123456/send");
curl_setopt_array($ch, [
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_CUSTOMREQUEST => "POST",
    CURLOPT_HTTPHEADER => [
        "Authorization: Bearer " . getenv("ARSEL_API_KEY"),
        "Content-Type: application/json",
    ],
    CURLOPT_POSTFIELDS => json_encode([
        "scheduled_at" => "2026-05-01T09:00:00Z",
    ]),
]);

$data = json_decode(curl_exec($ch), true);
if (curl_getinfo($ch, CURLINFO_HTTP_CODE) >= 400) {
    throw new Exception("{$data['name']}: {$data['message']}");
}

print_r($data);

---

Error Responses

400 Bad Request

{
  "status_code": 400,
  "name": "bad_request",
  "message": "Campaign is missing required fields and cannot be sent"
}

404 Not Found

{
  "status_code": 404,
  "name": "not_found",
  "message": "Campaign not found"
}

401 Unauthorized

{
  "status_code": 401,
  "name": "unauthorized",
  "message": "Invalid API Key"
}

---

Related: Cancel a campaign