Channels
How WhatsApp, SMS and email messages reach the Inbox, and the rules for each channel.
SmileLine connects three messaging channels: WhatsApp, SMS (via Twilio) and Email. This page explains how messages flow into the Inbox and what each channel allows, so you know what to expect when replying.
How conversations flow in
Once a channel is connected, inbound messages arrive in the Inbox automatically:
- A message from a number or address SmileLine already knows lands in that patient's existing thread.
- A message from an unknown sender opens a new conversation marked "Unknown contact" — link it to a patient so it lands on their timeline.
- A patient reply reopens a closed or snoozed conversation, so it always resurfaces in the Open tab.
Each patient has a single thread that can span channels. Their WhatsApp messages, texts and emails all appear in one conversation, and every message carries the icon of the channel it travelled on.
Choosing a channel for a reply
When a thread spans channels, the composer's channel picker decides which one your reply rides. It defaults to the channel the patient last wrote on. A channel is unavailable when its connection is disconnected or the patient has opted out — the picker greys it out and shows the reason.
Channel rules
WhatsApp allows free-text replies only within 24 hours of the patient's last message (the "24-hour window"). While the window is open, the composer shows a countdown when it's about to close. Once it closes, the composer switches to approved templates only — pick one to restart the conversation, reply on another channel, or leave an internal note instead. Starting a brand-new WhatsApp conversation also requires an approved template. See Message templates.
Attachments are supported while the window is open.
Plain text only — no attachments and no subject lines. Sent through your connected Twilio number.
Supports subject lines, formatted content and attachments. When replying, leave the subject blank to continue the thread's latest subject. Long emails are collapsed in the thread — click Show full email to expand.
Attachments on any channel are limited to 10 MB per file.
Connecting and managing channels
Channels are set up in Settings → Channels by an owner or admin: connect a WhatsApp number, a Twilio SMS number or an email address, then use Test to verify the connection. The full setup walkthrough, including the webhook and inbound-address details your provider needs, lives in Settings → Channels.
If no channel is connected yet, the New conversation dialog will tell you — connect one in Settings → Channels first.