Messaging Channels
SMS, email, WhatsApp queues, and reply handling
RCSZilla supports three messaging channels in the product: SMS, email, and WhatsApp replies. The public REST queue endpoint currently accepts sms and whatsapp. Email is sent through SMTP servers and campaign tooling in the web panel.
Channel Summary
| Channel | Where It Is Used | Delivery Path |
|---|---|---|
| sms | Direct API sending, campaigns, inbox replies, reminders | Queued with queue_sms, then sent by the Android device or provider flow. |
| WhatsApp queue items and reply automation | Queued with queue_sms using "channel": "whatsapp", then fetched by the Android app through poll. |
|
| Email campaigns from the web panel | Sent through configured SMTP servers. Email is not accepted by the queue_sms REST endpoint. |
Send SMS by API
Use queue_sms with "channel": "sms". The response returns the queued message ID.
{
"to": "+40700000000",
"message": "Your SMS text",
"channel": "sms"
}
Queue WhatsApp
Use the same endpoint with "channel": "whatsapp". The Android app receives WhatsApp queue items in the whatsapp array returned by poll.
{
"to": "+40700000000",
"message": "Your WhatsApp message",
"channel": "whatsapp"
}
WhatsApp Replies
Incoming replies are posted with submit_reply. If an auto-reply rule matches, the API returns reply and reply_queue_id so the app can send the response and mark it sent.
{
"from_phone": "+40700000000",
"message": "Customer reply text",
"channel": "whatsapp"
}
Email campaigns use SMTP servers configured in the web panel under Email Servers. Add and verify SMTP servers, then create an email campaign from Campaigns. Email delivery is separate from the mobile-app REST queue documented here.
Scheduled Delivery
For API queued SMS or WhatsApp messages, add scheduled_at to delay sending until a future date/time.
{
"to": "+40700000000",
"message": "Scheduled reminder",
"channel": "sms",
"scheduled_at": "2026-05-02 15:30:00"
}