RCSZilla Version 1.0

Webhooks

Real-time event notifications for incoming SMS, WhatsApp, and Email messages.

Overview

RCSZilla can send HTTP POST requests to your server whenever specific events occur. This lets you build real-time integrations without polling.

FieldDescriptionConfigured in
incoming_smsA new SMS message was received by your Android device.Devices → Control → Webhooks tab
incoming_whatsappA new WhatsApp message was received by your Android device.Devices → Control → Webhooks tab
incoming_emailA new email arrived in an IMAP inbox linked to your SMTP server.Email Servers → Edit → Incoming Email (IMAP) section
testA test event sent manually from the UI.Same as above

Setup

Incoming SMS / WhatsApp Webhook

  1. Go to Devices and click the control icon for your device.
  2. Open the Webhooks tab.
  3. Enter your endpoint URL (must accept POST, return 2xx within 10 seconds).
  4. Optionally set a Webhook Secret for HMAC signature verification.
  5. Click Save, then Send Test Webhook to verify.

Incoming Email Webhook

  1. Go to Email Servers and edit (or add) a server.
  2. Expand the Incoming Email (IMAP) section.
  3. Enable IMAP polling and fill in the IMAP host, port, encryption, and credentials.
  4. Enter a webhook URL and optional secret.
  5. Save. A cron job checks for new emails every 2 minutes.

Request Format

Headers

HeaderDescription
Content-Typeapplication/json
User-AgentRCSZilla-Webhook/1.0
X-RCSZilla-EventEvent type: incoming_sms, incoming_whatsapp, incoming_email, or test
X-RCSZilla-DeliveryUnique delivery ID (use for deduplication)
X-RCSZilla-Signaturesha256=<hex-hmac> — only present if you set a webhook secret. The HMAC is computed over the raw JSON body using SHA-256.

incoming_sms / incoming_whatsapp

Fired when the Android app calls submit_reply with a new message.

JSON
{
  "event": "incoming_sms",
  "timestamp": "2026-05-27T14:30:00Z",
  "data": {
    "id": 209,
    "from": "+40712345678",
    "message": "Yes, I want to book an appointment",
    "channel": "sms",
    "device_id": 6,
    "contact": {
      "id": 42,
      "name": "John Doe",
      "phone": "+40712345678"
    },
    "auto_reply": "Thanks! We will get back to you shortly."
  }
}

Field

FieldTypeDescription
eventstringincoming_sms or incoming_whatsapp
timestampstringISO 8601 UTC timestamp
data.idintID of the stored incoming message
data.fromstringSender phone number
data.messagestringMessage text
data.channelstringsms or whatsapp
data.device_idintDevice that received the message
data.contactobject|nullMatched contact (id, name, phone) or null if unknown sender
data.auto_replystring|nullAuto-reply text sent back, or null if no rule matched

incoming_email

Fired when the IMAP cron finds a new email in the configured mailbox.

JSON
{
  "event": "incoming_email",
  "timestamp": "2026-05-27T14:30:00Z",
  "data": {
    "id": 310,
    "from_email": "customer@example.com",
    "from_name": "John Doe",
    "to_email": "support@yourbusiness.com",
    "subject": "Re: Your order #1234",
    "body_text": "Hi, when will my order arrive?",
    "received_at": "2026-05-27T14:28:00Z",
    "smtp_server_id": 5
  }
}

Field

FieldTypeDescription
data.idintID of the stored email
data.from_emailstringSender email address
data.from_namestringSender display name
data.to_emailstringRecipient (your mailbox)
data.subjectstringEmail subject line
data.body_textstringPlain-text body (first 2000 chars)
data.received_atstringOriginal receive timestamp
data.smtp_server_idintWhich SMTP/IMAP server received this

Verifying Signatures

If you configure a webhook secret, each delivery includes an X-RCSZilla-Signature header. Verify it like this:

PHP
<?php
$payload = file_get_contents('php://input');
$secret  = 'whsec_your_secret_here';

$header    = $_SERVER['HTTP_X_RCSZILLA_SIGNATURE'] ?? '';
$expected  = 'sha256=' . hash_hmac('sha256', $payload, $secret);

if (!hash_equals($expected, $header)) {
    http_response_code(401);
    exit('Invalid signature');
}

$data = json_decode($payload, true);
// Process the event...
http_response_code(200);
echo json_encode(['ok' => true]);
Node.js
const crypto = require('crypto');

app.post('/webhook', (req, res) => {
  const payload = JSON.stringify(req.body);
  const secret  = 'whsec_your_secret_here';
  const sig     = req.headers['x-rcszilla-signature'] || '';
  const expected = 'sha256=' + crypto.createHmac('sha256', secret)
                                      .update(payload).digest('hex');

  if (sig !== expected) return res.status(401).send('Invalid signature');

  const { event, data } = req.body;
  console.log(`Received ${event}:`, data);
  res.json({ ok: true });
});
Python
import hmac, hashlib, json
from flask import Flask, request, abort

app = Flask(__name__)
SECRET = 'whsec_your_secret_here'

@app.route('/webhook', methods=['POST'])
def webhook():
    payload = request.get_data()
    sig     = request.headers.get('X-RCSZilla-Signature', '')
    expected = 'sha256=' + hmac.new(
        SECRET.encode(), payload, hashlib.sha256
    ).hexdigest()

    if not hmac.compare_digest(sig, expected):
        abort(401)

    data = json.loads(payload)
    print(f"Event: {data['event']}", data['data'])
    return {'ok': True}

Retry Policy

If your endpoint returns a non-2xx status code, times out (10 seconds), or is unreachable, the delivery is retried with exponential backoff:

AttemptDelay
1st retry1 minute
2nd retry5 minutes
3rd retry30 minutes
4th retry2 hours
5th retry (final)12 hours
*
After 5 failed attempts the webhook is marked as permanently failed. Successfully delivered webhooks are automatically cleaned up after 7 days. Failed deliveries are retained for 30 days.

List Webhook Deliveries

GET /?endpoint=webhook_deliveries

Returns a paginated list of webhook deliveries for the authenticated user, with status counts and optional filtering.

Query Parameters

FieldTypeDescription
statusstring optional Filter by status: pending, processing, sent, or failed.
event_typestring optional Filter by event type: incoming_sms, incoming_whatsapp, incoming_email, or test.
limitint optional Results per page (1–100). Default: 20.
offsetint optional Pagination offset. Default: 0.

Example Request

cURL
curl "https://api.rcszilla.com/?endpoint=webhook_deliveries&status=pending&limit=10" \
  -H "Authorization: Bearer YOUR-API-TOKEN"

Response

JSON
{
  "success": true,
  "total": 42,
  "limit": 10,
  "offset": 0,
  "counts": {
    "pending": 3,
    "sent": 38,
    "failed": 1
  },
  "deliveries": [
    {
      "id": 156,
      "event_type": "incoming_sms",
      "webhook_url": "https://your-server.com/hook",
      "status": "pending",
      "attempts": 0,
      "max_attempts": 5,
      "http_status": null,
      "last_error": null,
      "next_retry_at": "2026-05-27T14:31:00Z",
      "created_at": "2026-05-27T14:30:05",
      "last_attempt_at": null
    }
  ]
}

Status Counts

The counts object gives you a quick overview of all webhook states without paginating through every delivery. Use it for dashboard widgets or health checks.

FieldDescription
pendingQueued, waiting for next cron run or retry window.
processingCurrently being delivered by the cron worker.
sentSuccessfully delivered (HTTP 2xx). Auto-cleaned after 7 days.
failedAll retry attempts exhausted. Auto-cleaned after 30 days.

Get Webhook Delivery

GET /?endpoint=webhook_delivery

Returns a single webhook delivery by ID, including the full payload that was (or will be) sent to your endpoint.

Query Parameters

FieldTypeDescription
idint required The delivery ID returned by webhook_deliveries.

Example Request

cURL
curl "https://api.rcszilla.com/?endpoint=webhook_delivery&id=156" \
  -H "Authorization: Bearer YOUR-API-TOKEN"

Response

JSON
{
  "success": true,
  "delivery": {
    "id": 156,
    "event_type": "incoming_sms",
    "webhook_url": "https://your-server.com/hook",
    "payload": {
      "event": "incoming_sms",
      "timestamp": "2026-05-27T14:30:00Z",
      "data": {
        "id": 209,
        "from": "+40712345678",
        "message": "Yes, I want to book",
        "channel": "sms",
        "device_id": 6,
        "contact": {
          "id": 42,
          "name": "John Doe",
          "phone": "+40712345678"
        },
        "auto_reply": null
      }
    },
    "status": "sent",
    "attempts": 1,
    "max_attempts": 5,
    "http_status": 200,
    "last_error": null,
    "next_retry_at": null,
    "created_at": "2026-05-27T14:30:05",
    "last_attempt_at": "2026-05-27T14:30:08"
  }
}
*
Use webhook_deliveries?status=failed to monitor broken endpoints, or status=pending to check the queue depth. The counts field in the list response is ideal for health-check dashboards.

n8n Integration

To receive webhooks in n8n:

  1. Add a Webhook node to your workflow and copy its URL.
  2. Paste that URL into the webhook URL field in {APP_NAME} (Devices → Webhooks or Email Servers → IMAP).
  3. Test to confirm n8n receives the event.
  4. Connect downstream nodes to process the data (e.g., send a Slack message, update a CRM, trigger a reply).

Cron Setup

Add these cron jobs to your server:

crontab
# Fire pending webhooks (every minute)
* * * * * /usr/bin/php /path/to/send_sms/cron/process_webhook_queue.php

# Poll IMAP inboxes for new emails (every 2 minutes)
*/2 * * * * /usr/bin/php /path/to/send_sms/cron/process_incoming_emails.php