# SMS

## Overview

Welkin supports two-way SMS (text message) communication between care teams and patients. SMS is managed through Twilio and configured by your administrator.

## Sending an SMS

1. Open the patient profile or go to the **Communication Center**
2. Click **+ New Message** and select **SMS**
3. Verify the patient's mobile number is listed (or select from available numbers)
4. Type your message (standard SMS character limit applies; long messages are sent as MMS)
5. Click **Send**

## Receiving SMS from Patients

When a patient replies via SMS:

* The message appears in the patient's communication thread in the Communication Center
* A notification badge appears on the bell icon and in the Inbox
* The SMS is logged in the patient's communication history

## SMS Templates

Use pre-written templates to send common messages quickly. Click the **Templates** icon when composing an SMS to browse available templates. See [Communication Templates](/care/communication/communication-templates.md).

## SMS Opt-Out

Patients can opt out of SMS communications by replying STOP to any message. Welkin automatically records the opt-out and prevents further SMS to that number until the patient opts back in (by replying START).

Opt-out status is visible in the patient profile. Care team members cannot send SMS to opted-out patients.

## Sending Line

Your organization may have multiple SMS sending lines (phone numbers). When sending, you may be able to select which line to send from, or the system may assign one automatically based on your configuration.

## Twilio A2P Requirements

SMS requires Twilio A2P (Application-to-Person) registration. See [Twilio A2P](https://github.com/welkincloud-io/welkin-docs/blob/master/kb/integrations/twilio-a2p.md) for setup details.


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