Last modified: August 28, 2025
The Calling Extensions SDK enables apps to provide a custom calling option to HubSpot users directly from a CRM record, similar to HubSpot’s provided calling tool. When a user makes a call using your app, HubSpot will create an engagement on the activity timeline of the CRM record, then exchange data with your app to fill in the details. A calling extension consists of three main components:
  1. The Calling Extensions SDK, a JavaScript SDK that enables communication between your app and HubSpot.
  2. The calling settings endpoints, which are used to set the calling settings for your app. Each HubSpot account that connects to your app will use these settings.
  3. The calling iframe, which is where your app appears to HubSpot users and is configured using the calling settings endpoints.
If you don’t have an app, you can create a new app from the developer overview in your HubSpot account.

Please note:

The documentation below covers outbound calling via the SDK. Learn more about using the SDK to receive incoming calls (BETA).

Run the demo calling app

You have the option to test the Calling Extensions SDK on two different demo apps:
  • The demo-minimal-js features a minimal implementation of the SDK using JavaScript, HTML, and CSS. View how the SDK is instantiated in index.js.
  • The demo-react-ts features a real-life implementation of the SDK using React, TypeScript, and Styled Components to act as a blueprint for your app. View how the SDK is instantiated in useCti.ts.

Please note:

These demo apps aren’t fully functional calling apps and use mock data to provide a more realistic experience.

Install the demo calling app

You can run the demo apps with or without installation. To install the demo on your local environment:
  1. Install Node.js on your environment.
  2. Clone, fork, or download the ZIP of this repository.
  3. Open your terminal, and navigate to the root directory of the project.
  4. Run one of the following commands:
    • For the demo-minimal-js:
cd demos/demo-minimal-js && npm i && npm start
  • For the demo-react-ts:
cd demos/demo-react-ts && npm i && npm start
These will switch to the desired demo directory, install the Node.js dependencies required for the project using the npm CLI, and start the app.

Please note:

The npm start command will automatically open a new tab in your browser at https://localhost:9025/, and you may need to bypass a “Your connection is not secure” warning in order to access the application.

Launch the demo calling app from HubSpot

  1. Navigate to your records:.
    • Contacts: In your HubSpot account, navigate to Contacts > Contacts.
    • Company: In your HubSpot account, navigate to Contacts > Companies.
  2. Open your browser’s developer console, and run the following command:
    • If you’ve completed the installation steps, for the demo-minimal-js or the demo-react-ts:
localStorage.setItem('LocalSettings:Calling:installDemoWidget', 'local');
  • If you’ve skipped the installation steps:
    • For the demo-minimal-js:
localStorage.setItem('LocalSettings:Calling:installDemoWidget', 'app:js');
  • For the demo-react-ts:
localStorage.setItem('LocalSettings:Calling:installDemoWidget', 'app');
  1. Refresh the page, and click the Call icon in the left sidebar. Click the Call from dropdown menu, and select the name of the demo app from step 2 (e.g. Demo App Local, Demo App JS, Demo App React).
call-app-in-record
  1. Click Call to see how the demo app integrates with HubSpot via the Calling Extensions SDK. You can also see the events logged to your browser’s developer console.
calling-sdk-in-app

Install the Calling Extensions SDK on your calling app

To add the Calling Extensions SDK as a Node.js dependency to your calling app:
  • For npm, run:
npm i --save @hubspot/calling-extensions-sdk
  • For yarn, run:
yarn add @hubspot/calling-extensions-sdk

Using the Calling Extensions SDK

The Calling Extensions SDK exposes a simple API for HubSpot and a calling app to exchange messages. The messages are sent through methods exposed by the SDK and received through eventHandlers. You can find a full list of the available events in the Events section. The following is a description of the events:
  1. Dial number: HubSpot sends the dial number event.
  2. Outbound call started: App notifies HubSpot when the call is started.
  3. Create engagement: HubSpot creates a call engagement with minimal information if requested by the app.
  4. Engagement created: HubSpot created an engagement.
  5. EngagementId sent to App: HubSpot sends the engagementId to the app.
  6. Call ended: App notifies when the call is ended.
  7. Call completed: App notifies when the user is done with the app user experience.
  8. Update engagement: App fetches the engagement by the engagementId, then merges and updates the engagement with additional call details. Learn more about updating a call engagement via the APIor via the SDK.
To begin, create an instance of the CallingExtensions object. You can define the behavior of your extension by providing an option’s object when you create your extensions instance. This option’s object provides an eventHandlers field where you can specify the behavior of your extension. The following code block illustrates the available options and event handlers you can define:
import CallingExtensions from "@hubspot/calling-extensions-sdk";

const options = {
  /** @property {boolean} debugMode - Whether to log various inbound/outbound debug messages to the console. If false, console.debug will be used instead of console.log */
  debugMode: boolean,
  // eventHandlers handle inbound messages
  eventHandlers: {
    onReady: () => {
      /* HubSpot is ready to receive messages. */
    },
    onDialNumber: event => {
      /* HubSpot sends a dial number from the contact */
    },
    onCreateEngagementSucceeded: event => {
      /* HubSpot has created an engagement for this call. */
    }
    onEngagementCreatedFailed: event => {
      /* HubSpot has failed to create an engagement for this call. */
    }
    onUpdateEngagementSucceeded: event => {
      /* HubSpot has updated an engagement for this call. */
    },
    onUpdateEngagementFailed: event => {
      /* HubSpot has failed to update an engagement for this call. */
    }
    onVisibilityChanged: event => {
      /* Call widget's visibility is changed. */
    }
  }
};

const extensions = new CallingExtensions(options);

Test your app

In order to launch the calling extensions iFrame for end users, HubSpot requires the following iFrame parameters.
{
   name: string /* The name of your calling app to display to users. */,
   url: string  /* The URL of your calling app, built with the Calling Extensions SDK */,
   width: number /* The iFrame's width */,
   height: number /* The iFrame's height */,
   isReady: boolean /* Whether the widget is ready for production (defaults to true) */,
   supportsCustomObjects : true /* Whether calls can be placed from a custom object */
}

Using the calling settings endpoint

Using your API tool (e.g. Postman), send the following payload to HubSpot’s settings API. Ensure you get the APP_ID of your calling app and your app DEVELOPER_ACCOUNT_API_KEY.

Please note:

The isReady flag indicates whether the app is ready for production. This flag should be set to false during testing.
# Example payload to add the call widget app settings
curl --request POST \
 --url 'https://api.hubapi.com/crm/v3/extensions/calling/APP_ID/settings?hapikey=DEVELOPER_ACCOUNT_API_KEY' \
 --header 'accept: application/json' \
 --header 'content-type: application/json' \
 --data '{"name":"demo widget","url":"https://mywidget.com/widget","height":600,"width":400,"isReady":false}'

# Note that this endpoint also supports PATCH, GET and DELETE

Override your extension settings using localStorage

You can override any of your extension settings for testing purposes. Open your browser developer console from a HubSpot tab, edit the settings below, and run the command:
const myExtensionSettings = {
  isReady: true,
  name: 'My app name',
  url: 'My local/qa/prod URL',
};

localStorage.setItem(
  'LocalSettings:Calling:CallingExtensions',
  JSON.stringify(myExtensionSettings)
);

Get your app ready for production

Once you have set your app settings using the calling settings endpoint, use the PATCH endpoint to change isReady to true.
# Example payload to add the call widget app settings

curl --request PATCH \
 --url 'https://api.hubapi.com/crm/v3/extensions/calling/APP_ID/settings?hapikey=DEVELOPER_ACCOUNT_API_KEY' \
 --header 'accept: application/json' \
 --header 'content-type: application/json' \
 --data '{"isReady":true}'

Publish your calling app to the HubSpot marketplace

Once your app is set up, users can install it into their account using the app’s install URL. If you want to list it publicly for other HubSpot users to find, you can also choose to list it on the HubSpot App Marketplace. This is not necessary if the app is for internal use only.

Events

Available calling events:

Sending messages to HubSpot

The extensions object provides the following event handlers that you can invoke to send messages to HubSpot or to specify other associated behavior. See examples below.

initialized: Required

Send a message indicating that the soft phone is ready for interaction.
const payload = {
  isLoggedIn: boolean,
  engagementId: number,
  isAvailable: boolean,
};

extensions.initialized(payload);
PropertyTypeDescription
isLoggedInBooleanChecks if a user is logged in or not.
engagementIdNumberA HubSpot created engagement ID.
isAvailableNumberChecks if a user is available or not.

userAvailable

Sends a message indicating that the user is available.
extensions.userAvailable();

userUnavailable

Sends a message indicating that the user is unavailable.
extensions.userUnavailable();

userLoggedIn

Sends a message indicating that the user has logged in.
// This message is only needed when user isn't logged in when initialized
extensions.userLoggedIn();

userLoggedOut

Sends a message indicating that the user has logged out.
extensions.userLoggedOut();

incomingCall

Sends a message to notify HubSpot that an incoming call has started.
const callInfo = {
  externalCallId: string,
  callStartTime: number,
  createEngagement: boolean,
  fromNumber: string,
  tonumber: string,
};
extensions.incomingCall(callInfo);
PropertyTypeDescription
externalCallIdStringA calling app created call ID. Used to enable calling in help desk.
callStartTimeNumberStart time of call, in milliseconds.
createEngagementBooleanWhether HubSpot should create an engagement for this call or not. When true, HubSpot will respond with onCreateEngagementSucceeded or onCreateEngagementFailed.
fromNumberStringThe caller’s number. Required parameter.
toNumberStringThe recipients phone number.

outgoingCall

Sends a message to notify HubSpot that an outgoing call has started.
const callInfo = {
  phoneNumber: string /** @deprecated Use toNumber instead **/,
  callStartTime: number,
  createEngagement: true,
  toNumber: string,
  fromNumber: string,
  dialingContext: onDialEventPayload,
};
extensions.outgoingCall(callInfo);
PropertyTypeDescription
callStartTimeNumberStart time of call, in milliseconds.
createEngagementBooleanWhether HubSpot should create an engagement for this call or not. When true, HubSpot will respond with onCreateEngagementSucceeded or onCreateEngagementFailed.
toNumberStringThe recipients phone number.
fromNumberStringThe caller’s number. Required parameter.
dialingContextObjectThe dialing context is used for ticket and/or engagement creation when applicable. The object includes all properties of the onDialNumber payload. This property helps ensure data consistency by passing back the full dialing context between HubSpot and your third party app.

callAnswered

Sends a message to notify HubSpot that an outgoing call is being answered.
const payload = {
  externalCallId: string,
};
extensions.callAnswered();
PropertyTypeDescription
externalCallIdStringA calling app created call ID. Used to enable calling in help desk.

callEnded

Sends a message to notify HubSpot that the call has ended.
// After receiving the call ended event, the user can navigate away, can close the call widget.
extensions.callEnded({
  externalCallId: string,
  engagementId: number,
  callEndStatus: EndStatus,
});
PropertyTypeDescription
externalCallIdStringA calling app created call ID. Used to enable calling in help desk.
engagementIdNumberA HubSpot created engagement ID.
callEndStatusEnumerationThe status of the call when ended. Statuses available:
  • COMPLETED
  • FAILED
  • CANCELED
  • BUSY
  • NO_ANSWER
  • REJECTED
  • MISSED

callCompleted

Sends a message to notify HubSpot that the call has completed. Engagement properties are owned by HubSpot, and no longer need to be created or updated manually (see highlighted).

Please note:

The hideWidget property will be ignored when the user is in a task queue with the Call task type.
// After receiving the call completed event, HubSpot will
//   1) insert the engagement into the timeline
//   2) set the default associations on the engagement
//   3) closes the widget unless `hideWidget` is set to false.
//   4) update the engagement with any engagement properties
const data = {
  engagementId: number,
  hideWidget: boolean,
  engagementProperties: { [key: string]: string },
  externalCallId: string,
}
extensions.callCompleted(data);
PropertyTypeDescription
engagementIdNumberA HubSpot created engagement ID.
hideWidgetBooleanWhether the widget should be hidden when the call is ended. Optional parameter. Defaults to true.
engagementPropertiesStringOpt in to hs owned engagements by adding properties. Causes HubSpot to respond with onUpdateEngagementSucceeded or onUpdateEngagementFailed.
externalCallIdStringA calling app created call ID. Used to enable calling in help desk.

publishToChannel

Publishes the call to a connected channel. This isn’t needed for HubSpot-owned engagements.
const payload = {
  externalCallId,
  engagementId,
};
extensions.publishToChannel(payload);
PropertyTypeDescription
externalCallIdStringA calling app created call ID. Used to enable calling in help desk.
engagementIdNumberA HubSpot created engagement ID.
This event is called when navigating to a record.
onNavigateToRecord {
    const {
      engagementId: number,
      objectCoordinates: object coordinates
    } = data;
      ...
}
PropertyTypeDescription
engagementIdNumberA HubSpot created engagement ID.
objectCoordinatesObject coordinatesReferences a portalId, objectId, and objectTypeID.

sendError

Sends a message to notify HubSpot that the calling app has encountered an error.
// After receiving the sendError event, HubSpot will display an alert popup to the user with the error message provided.
const data = {
  message: string,
};
extensions.sendError(data);
PropertyTypeDescription
messageStringError message to be displayed in the alert popup.

resizeWidget

Sends a message to notify HubSpot that the calling app needs to be resized.
// After receiving the resizeWidget event, HubSpot will use the provided height and width to resize the call widget.
const data = {
  height: number,
  width: number,
};
extensions.resizeWidget(data);
PropertyTypeDescription
heightNumberDesired height of the call widget.
widthNumberDesired width of the call widget.

Receive messages from HubSpot

The extensions object provides the following event handlers that you can invoke when receiving messages in HubSpot or to specify other associated behavior. See examples below.

onReady

Message indicating that HubSpot is ready to receive messages.
// Example snippet for handling onReady event
onReady() {
    extensions.initialized(payload);
}
PropertyTypeDescription
engagementIdNumberA HubSpot created engagement ID.
iframeLocationEnumwidget: drag and drop widget shown in record pages when calling app doesn’t support inbound inbound calling.
remote: frame in the navigation bar when calling app supports inbound calling.
window: iframe in the calling window when calling app supports inbound calling.
ownerIdString or NumberThe ID of the logged in user in HubSpot.
PortalIdNumberThe ID of the HubSpot account.
userIdNumberThe ID of the HubSpot user.

onDialNumber

This event will trigger when a user in HubSpot triggers an outbound call. The onDialNumber event will provide a payload that includes all the pertinent fields associated with the call. These fields are detailed in the table below:
onDialNumber(data) {
  const {
    phoneNumber: string,
    ownerId: number,
    subjectId: number,
    objectId: number,
    objectType: CONTACT | COMPANY,
    portalId: number,
    countryCode: string,
    calleeInfo {
        calleeId: number,
        calleeObjectTypeId: string,
    },
    startTimestamp: number,
    toPhoneNumberSrc: string,
   } = data;
    ...
}
PropertyTypeDescription
phoneNumberStringThe phone number of the person that the HubSpot user called.
ownerIdString or NumberThe ID of the logged in user (in HubSpot).
subjectIdNumberThe ID of the subject.
objectIdNumberObject type of the phone number.
objectTypeStringThe object type associated with the phone number that was dialed (e.g., the phone number of the contact or company). The possible values here are "CONTACT" or "COMPANY".
portalIdNumberThe ID of the HubSpot portal.
countryCodeStringThe country code of the phone number.
calleeInfoArrayInformation about the callee. Should include the following:
  • calleeID: number
  • calleeObjectTypeId: string
startTimestampNumberTimestamp of the start of the call.
toPhoneNumberSrcStringThe name of the phone numbers’ property in HubSpot. The property can be a standard property value or a custom property. For example, a contact may have three contact phone numbers, one may be labeled Office, another may be labeled Personal and the other may be labeled Mobile.

onEngagementCreated

Deprecated. Use onCreateEngagementSucceeded instead.
/** @deprecated Use onCreateEngagementSucceeded instead **/
onEngagementCreated(data) {
    const {
      engagementId: number,
    } = data;
      ...
}
PropertyTypeDescription
engagementIdNumberA HubSpot created engagement ID.

onCreateEngagementSucceeded

HubSpot sends a message to notify the calling app partner that the engagement update succeeds.
onCreateEngagementSucceeded: (event) => {};

onCreateEngagementFailed

HubSpot sends a message to notify the calling app partner that the engagement creation failed.
onCreateEngagementFailed: (event) => {};

onNavigateToRecordFailed

This event is called when navigating to a record fails.
onNavigateToRecordFailed {
    const {
      engagementId: number,
      objectCoordinates: object coordinates
    } = data;
      ...
}
PropertyTypeDescription
engagementIdNumberA HubSpot created engagement ID.
objectCoordinatesObject coordinatesReferences a portalId, objectId, and objectTypeID.

onPublishToChannelSucceeded

This event is called when publishing to a channel succeeds.
onPublishToChannelSucceeded{
    const {
      engagementId: number,
      externalCallId: string
    } = data;
      ...
}
PropertyTypeDescription
engagementIdNumberA HubSpot created engagement ID.
externalCallIdStringA calling app created call ID. Used to enable calling in help desk.

onPublishToChannelFailed

This event is called when publishing to a channel fails.
onPublishToChannelFailed{
    const {
      engagementId: number,
      externalCallId: string
    } = data;
      ...
}
PropertyTypeDescription
engagementIdNumberA HubSpot created engagement ID.
externalCallIdStringA calling app created call ID. Used to enable calling in help desk.

onCallerIdMatchSucceeded

This event is called when the caller ID match succeeds.
onCallerIdMatchSucceeded: (event) => {};

onCallerIdMatchFailed

This event is called when the caller ID match fails.
onCallerIDMatchFailed: (event) => {};

onVisibilityChanged

Message indicating if the user has minimized or hidden the calling app.
onVisibilityChanged(data) {
    const { isMinimized, isHidden } = data;
    ...
}

defaultEventHandler

Default handler for events.
defaultEventHandler(event) {
   console.info("Event received. Do you need to handle it?", event);
}

Calling SDK | Frequently Asked Questions

How is user authentication handled?

The calling app should handle authentication.

Is Calling Extensions hosted on a CDN?

Yes. You can install the Calling Extensions SDK via jsDeliver. For example, to install calling-extensions-sdk@0.2.2, you can use https://cdn.jsdelivr.net/npm/@hubspot/calling-extensions-sdk@0.2.2/dist/main.js.

When should an engagement be created versus updated?

A user can initiate a call from inside the HubSpot UI and outside the HubSpot UI (e.g. mobile app, redirected number, etc.) If a call is initiated from within HubSpot UI, HubSpot will create a call engagement and send the engagement to the calling app. Once the call finishes, the call app can update this engagement with additional call details. If a call is initiated outside of HubSpot UI, the app should create the call engagement.

What scopes are required as a part of the integration?

Add contacts and timeline scopes are required. These scopes ensure your application has access to contacts and the ability to create and update call engagements in the CRM.

Can this functionality be added to an already existing application in the marketplace or do I create a new app?

If you already have an existing app that serves the calling use case then you can directly add this functionality to your existing app. All customers who already have your app installed will get access to this new functionality without having to install the app again.

Can I integrate my existing soft phone application in the SDK?

Yes, integrating your existing soft phone application should be very easy. Just follow the steps in the documentation above to have your application up and running.

Can users use multiple integrations at the same time?

Yes, users can use multiple third-party calling integrations at the same time. They can use the provider switcher presented after clicking on the call button to seamlessly switch between providers.

Can free users install app integrations?

Yes, all users can install the app.

If a user already has my app installed, does the integration automatically show up?

Yes, if a user already has installed your app, and you are updating the same app with the calling extensions, the integration will automatically show up. Currently, there is no way for the developer to enable the calling app only to a subset of customers.

Can any user install or uninstall an app?

No, only users who have necessary permissions can install and uninstall an app. Learn more about how to review a user’s permissions.

Can I create a custom calling property?

Yes, you can create a custom calling property using the properties API.

Can I place a call from a custom object?

Yes, calling integrations can place calls from custom objects as long as they only use the SDK to create the call. Each integration will need to verify that they only use the Calling SDK to create calls and to notify HubSpot in the outgoingCall event. First, verify that the integration is using the Calling SDK to create engagements in the outgoingCall event:
outgoingCall({ createEngagement: true });
If createEngagement is true, learn how to update your app information here. Here is the example for the entire outgoingCall event:
const callInfo = {
  phoneNumber: string, // optional unless call is initiated by the widget
  createEngagement: true // whether HubSpot should create an engagement for this call
  callStartTime: number // optional unless call is initiated by the widget
};
extensions.outgoingCall(callInfo);