Getting External Answer Data During an Interview

Note: only users with the Site Administrator or Integration Administrator user role can manage webhooks.

The Custom Interview Event webhook enables you to populate HotDocs interviews with answer data retrieved from your own web application.


This webhook has the following prerequisites:

  • An Author template containing an Interview Event dialog element; this is the component which triggers the webhook in interview.
  • You must know the Event Name used in the interview event dialog element; this is used when setting the Interview Event Name for the webhook.
  • Creating a Webhook – you must have an existing webhook that:
    • Uses the Custom Interview Event type
    • The Interview Event Name property matches the Event Name in the interview event dialog element
  • Answer JSON that matches the variable names and structure of the Author template
  • An endpoint on your web application that accepts a POST request and returns a set of answer data


When you create a custom interview event webhook, you specify an endpoint on your web application that accepts a POST request and returns answer data. This answer data must be in the HotDocs answer JSON format. 

The POST request to the endpoint is activated when a user opens an Advance interview and clicks an interview event dialog element that has the same Event Name property as your webhook. When the data is returned to the interview from your endpoint, Advance overlays the answer data into the interview, populating the answer fields for your user.

Your Existing Webhook

This example supposes that you have an existing webhook with the following properties:

  • Name – WebhookExample02
  • URLhttps://localhost/WebhookExampleApp/GetAnswerData
  • Event Type Custom Interview Event (sends request to retrieve answer data when a user clicks the interview event dialog element)
  • Interview Event NameGetAnswerData
  • Authentication MethodHMAC
  • Active StatusActive
  • Untrusted SSL CertificatesNo

The URL for the webhook should point to the POST endpoint in your own web application.

The Interview Event Name must match the Event Name property for the interview event dialog in your template.

Authentication method

The token specified in the webhook is passed in the request sent to your endpoint, in the Authorization header. HMAC authentication is the recommended authentication method to authenticate requests from Advance to your own application.

See also Authentication Types

The correct Request Verb for your webhook should be POST. If you have an existing webhook which uses a GET request verb, it is advised you edit the webhook to use POST.

The GET request verb is now deprecated and is only available for legacy compatibility.

Data Sent from Advance to your Endpoint

When the Custom Interview Event webhook is activated by a user, the webhook sends a POST request to your endpoint. The request contains a JSON string that includes the following data:

  • linkedVariable — the name of the linked variable in the interview event dialog element that activated the webhook
  • userContextData — the user context data for the template; this includes details about the user that activated the webhook

For example:

    "linkedVariable": { "ParameterValue": "EmployeeNameTextVariable" },
    "userContextData": {
        "UserId": "8727d822-7b4a-5f6d-ab56-781f498af6cc", 
        "UserFirstName": "John",
        "UserLastName": "MacDiarmid",
        "UserEmailAddress": "",

You can use this information when constructing the data you will return to Advance. For example, if you need to look up information specific to the user making the request.

Data Sent from your Endpoint to Advance

The response sent back to Advance from your endpoint must be a JSON string that conforms to the HotDocs answer JSON format. For example, this answer set returns values for text, number, date, true/false, multi select, and repeat variables:

    {""n"":""textVar1"",""t"":""TX"",""v"":""Francis Smith""},
    {""n"":""dateVar1"",""t"":""DA"",""v"":""31 12 1999""},
    {""n"":""multiSelectVar1"",""t"":""TL"",""v"":{""v"":[""Option A"", ""Option B""]}},
    {""n"":""repeatVar1"",""t"":""TX"",""v"":[""Employed Full-Time"", ""Employed Part-Time"", ""Unemployed""]}


Getting Answer Data from an Existing Interview

You can use the HotDocs JavaScript API HD$.GetJSONAnswers function with an open HotDocs interview to quickly generate an example answer set. Running the command in the console of your browser's Developer Tools window retrieves the JSON answer data from the in-progress interview.

Validating Your Answer Data

You should validate your answer data before sending it to Advance. See Validating HotDocs Answer Sets for more information.

JSON Response Data Size

The size of JSON response data is limited to 200Kb by default. If your response data is often larger than this, you can change the default allowable size by adding the ExternalAnswersMaxBytes setting to your HdaInstallerSettings.json file. In between the "SiteSettings": braces add the following setting, replace 200 with the number of bytes you require:

"ApiSiteSettings.AppSettings.ExternalAnswersMaxBytes": 200,

This setting can be added before the installation of Advance. If you have already installed Advance, you can add this setting to the installer settings file and run the Hdainstaller.exe setting gu installer command. This uses the updated installer settings file to update the configuration of your installed version of Advance.

If other settings are listed below, ensure the comma at the end of the ExternalAnswersMaxBytes setting is included. If you add the setting below all other settings, then a comma is not required.

Please note that large JSON response data files can affect interview performance.

This setting affects custom interview and load interview event webhooks.