Initiate an outbound call

Zoom supports various URI schemes that allow users to launch the Zoom Phone client by clicking a secure hyperlink or a button.

This guide provides you with an overview of the supported URI schemes that you can use to redirect your app users to the Zoom Phone client to make outbound calls.


To use these schemes, the user (caller) must meet the following prerequisites:

Supported URI schemes

Zoom supports URI schemes to launch the Zoom Phone client and place calls.

  • callto
  • tel
  • zoomphonecall


  • Basic zoomphonecall URI support for iOS excluding callerid and seccall parameters
  • No zoomphonecall and tel support for Android due to the system security limitations

callto and tel URI schemes

The callto and tel URI schemes are popular industry standard schemes. You can use either of these schemes to launch the Zoom Phone client.

Implement the callto scheme with the following URL format:

  • callto:{phoneNumberToCall}
  • Example: callto:+123456789

Implement the tel scheme with the following URL format:

  • tel:{phoneNumberToCall}
  • Example: tel:+123456789

zoomphonecall URI scheme

You can use the zoomphonecall scheme to make calls.

The callerid parameter

You can change how the user's default Caller ID is displayed using this parameter. The zoomphonecall://{1234567}?callerid={10001} will call out with 10001 as the caller ID although it is actually 20002, for example. Note that the caller ID has to be an extension or an E.164 number. Use of this parameter does not change the default Caller ID in the Zoom Phone client.


Upon successful execution of zoomphonecall://{phoneNumbertoCall}, the Zoom client launches and auto-dials the number that is entered.


  • zoomphonecall://{phoneNumbertoCall}?cat=seccall&token={jwttoken}

(Optional) You can generate a JWT token in the following format:

"iss": "Enter your OAuth App Client ID.",
"iat": "Enter the current epoch timestamp in seconds in long format. Note that the value of this field should not be a string.",
"exp": "Enter the expiration timestamp for the JWT in seconds in long format. Note that the value of this field should not be a string.",
"oid": "Enter the phone number to call. This value should match the number provided in the URI scheme.",
"uid": "Enter the user ID of the user on whose behalf the call is to be placed. The user with this userId must be logged into the Zoom Client app using their Zoom account."


  • The query parameters above are optional and you may be able to call without authentication: cat=seccall&token={jwttoken}. Token verification is enabled for Zoom client version 5.0.24978.0517 or higher.
  • The URI scheme is a way to launch the Zoom client. The client ultimately manages user authorization.

After clicking on a button or a hyperlink associated with the scheme, the user will be prompted to confirm whether or not they'd like to open the Zoom app.

After confirming to open the app, the Zoom Phone tab is displayed. The phone number included in the scheme will be copied and displayed when the Zoom Phone client is opened via the scheme.

The user has to click the call button to place a call when the JWT token is appended.

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