# Initiate an outbound SMS ## Zoom SMS handler for initiating outbound SMS Zoom SMS Handler seamlessly initiates outbound SMS messages from third-party applications directly in the Zoom client. A dedicated handler URI scheme makes it easy to pre-fill phone numbers from external apps in Zoom to initiate SMS communications. **Handler URI scheme** ```plaintext zoomphonesms://{recipient_nr}?callerid={from_nr} ``` ## Initiate outbound SMS messages Zoom provides support for various URI schemes that empowers you to send SMS messages from the Zoom client directly from your applications. ## Prerequisites Before using these schemes, ensure the following prerequisites: - Installation of the latest version of the Zoom client with an active session. (Zoom client 6.1.0 and above for both desktop and mobile clients) - Possession of a valid Zoom Phone number that enables you to send and receive SMS. ## Supported URI schemes Zoom extends support for the following URI scheme to seamlessly launch the Zoom client and send SMS messages: `zoomphonesms://{recipient_nr}?callerid={from_nr}` ## Implement the SMS scheme ### Recipient number The recipient's phone number follows immediately after the scheme component, indicated by a colon (`:`) and two slashes (`//`). This parameter is mandatory and specifies the recipient who will receive the message. ### CallerID parameter The `callerid` parameter allows users to specify the desired caller ID for the outbound SMS message. For example `zoomphonesms://+123456789?callerid=+16692520210` initiates an SMS message with the specified `callerid +16692520210`. Note that the `callerid` must adhere to Zoom's format requirements. If the caller ID is invalid, we ignore the parameter. #### Streamlined SMS messaging The Zoom SMS Handler simplifies outbound SMS messaging. As a result, you can prefill phone numbers from third-party apps into Zoom with the designated handler URI scheme.