Dynamic inputs

  • Release version: Xanadu
  • Updated February 5, 2025
  • 5 minutes to read
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    Summary of Dynamic inputs

    Dynamic inputs enable action authors in ServiceNow Flow Designer to generate and display lists of inputs dynamically during flow configuration. They can show related action inputs, record fields, or choice list options, making flows more adaptable without needing manual updates when data structures change. Dynamic inputs require the ServiceNow Flow Designer - Introspection plugin and are not available in the base system.

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    Key Features

    • Dynamic Choice: Retrieves a list of choice values for an action input.
    • Dynamic Inputs: Gathers arbitrary additional action inputs to extend an action's configuration.
    • Dynamic Template: Dynamically collects fields from a selected record type, allowing flow authors to pick fields without action changes when the record structure updates.
    • Data Gathering Actions: Specialized actions designed to collect data (often via REST calls) for dynamic inputs. They must output JSON formatted data with a data property and adhere to limits such as max 5000 items for choice or template inputs.

    Practical Guidelines

    • Dynamic inputs are ideal for third-party integrations, allowing flows to fetch live data from external systems.
    • Data gathering actions have a default timeout of 300 seconds; this can be adjusted via the snflowdesigner.syncactionexecutiontimeoutinseconds system property.
    • Scripting errors in data gathering actions can prevent dynamic inputs from receiving data; error messages will notify authors of such issues.
    • Limit dynamic inputs type inputs to a maximum of 40 input values to avoid memory and rendering issues.
    • For dynamic choice and dynamic template inputs, do not exceed 5000 array items in the JSON output to maintain performance.

    Supported Data Types

    Dynamic inputs support a specific set of ServiceNow AI Platform data types, including choice, datetime, decimal, email, HTML, integer, password2, reference, and string. Action authors can customize labels, names, and default values for these inputs while adhering to the required data type definitions.

    Getting Started

    ServiceNow customers can begin leveraging dynamic inputs by:

    • Creating data gathering actions for dynamic choice inputs to generate choice lists dynamically.
    • Building data gathering actions for dynamic templates to retrieve record field values dynamically.
    • Developing data gathering actions for dynamic inputs type inputs to add arbitrary inputs dynamically.
    • Configuring dynamic inputs within actions and adding those actions to flows for flexible, data-driven input generation.

    Generate a list of action inputs or input values each time that someone configures the action in a flow. Dynamic inputs can display a list of related action inputs, a list of fields from a record, or a list of options available in a choice list.

    Note:
    Dynamic inputs are not available in the base system. To use dynamic inputs in Workflow Studio, you must Request an Integration Hub plugin. Dynamic inputs are part of the ServiceNow Flow Designer - Introspection [com.glide.hub.flow_designer_introspection] plugin.
    During flow design, dynamic inputs retrieve values and display them as inputs within an action dynamically. These types of dynamic inputs are available to action authors.
    Dynamic Choice
    The Dynamic Choice type input gathers a list of choice values to display. For more information on building a dynamic choice, see Create a data gathering action for a dynamic choice.
    Dynamic Inputs
    The Dynamic Inputs type input gathers a list of additional action inputs to display. Use Dynamic Inputs to add arbitrary inputs to an action. For more information on building dynamic inputs, see Create a data gathering action for a dynamic inputs type input.
    Dynamic Template
    The Dynamic Template type input gathers a list of fields from a dynamically selected record type. Flow authors can then select which fields to include in their flow. Because the list of fields is dynamically generated, you don't have to change the action when fields are added or removed from the source table. For more information on building a dynamic template, see Create a data gathering action for a dynamic template.
    There are three general steps to using dynamic inputs.
    1. An action author creates a data gathering action to generate dynamic data.
    2. An action author creates an action with a dynamic input and configures the dynamic input to call the data gathering action.
    3. A flow author adds the action to a flow and configures the action with dynamically gathered data.

    Data gathering actions

    A data gathering action collects data to be used by other actions. Data gathering actions are intended to be called from dynamic inputs rather than be added directly to a flow. Data gathering actions typically collect data from third-party systems using a REST call. All data gathering actions must meet these requirements and constraints.
    • The action has a script step that contains an output variable of type JSON.
    • The action has an output named output of type JSON whose value is derived from the script step's JSON output variable.
      Note:
      The action can have multiple outputs but can only have one of type JSON.
    • The script step formats the JSON output to have a property named data.
    • The JSON output should not return more than 5000 choice options, field template values, or array element items when the data is intended for a dynamic choice or a dynamic template input.
      Note:
      Dynamic choice and dynamic template inputs can only display up to 5000 choice options or 5000 template values from the JSON output.
    • The action waits for up to 300 seconds (5 minutes) to gather data before it times out.
      Note:
      To change the timeout period for all actions, modify the value of the sn_flow_designer.sync_action_execution_timeout_in_seconds system property.

    Supported dynamic input data types

    Dynamic inputs support a limited number of ServiceNow AI Platform data types. You can use the example JSON to build your own dynamic inputs. You can change the values of the label and name properties to met your needs. The type property must specify a ServiceNow AI Platform data type name. For more information about ServiceNow AI Platform field data types and how to configure them, see Field types.

    Table 1. Dynamic input data types supported
    Input data type Example JSON
    Choice 
    { 
    data: [{
      label: 'Choice type input',
      name: 'choicetype',
      defaultValue: 'choice_1',
      type: 'choice',
      choices: [
          { label: 'Choice 1', value: 'choice_1' },
          { label: 'Choice 2', value: 'choice_2' }
      ]
    }]
  }
    Datetime 
    { 
    data: [{
      label: 'Datetime type input',
      name: 'datetimetype',
      type: 'datetime',
    }]
  }
    Decimal 
    { 
    data: [{
      label: 'Decimal type input',
      name: 'decimaltype',
      type: 'decimal',
    }]
  }
    Email 
    { 
    data: [{
      label: 'Email type input',
      name: 'emailtype',
      type: 'email',
    }]
  }
    HTML 
    { 
    data: [{
      label: 'HTML type input',
      name: 'htmltype',
      type: 'html',
    }]
  }
    Integer 
    { 
    data: [{
      label: 'Integer type input',
      name: 'integertype',
      type: 'integer',
    }]
  }
    Password 2 
    { 
    data: [{
      label: 'Password2 type input',
      name: 'password2type',
      type: 'password2',
    }]
  }
    Reference 
    { 
    data: [{
      label: 'Reference type input',
      name: 'referencetype',
      reference: 'sys_user',
      type: 'reference',
    }]
  }
    String 
    { 
    data: [{
      label: 'String type input',
      name: 'stringtype',
      defaultValue: 'abcdef',
      type: 'string',
      mandatory: true
    }]
  }

    General guidelines

    Consider dynamic inputs for third-party integrations
    Dynamic inputs let you create flows that fetch data dynamically from external sources. In third-party integrations, dynamic inputs can provide data values that pertain to a particular endpoint. For more information on setting up third-party integrations with Workflow Studio, see IntegrationHub.
    Be aware of the time required to retrieve large amounts of data
    By default, dynamic inputs have up to 300 seconds to gather data before they time out. If your data gathering action needs more time to gather data, set the sn_flow_designer.sync_action_execution_timeout_in_seconds system property to a higher value. However, don't use long timeout values for interactive flows where an end user must enter or select a value.
    Be aware of scripting errors
    Because all data gathering actions use a script step, potential errors could occur from scripting. When using scripts to output JSON variables for your dynamic inputs, you may encounter errors that prevent inputs from receiving the JSON values they need. When a dynamic input scripting error occurs, the following warning message may appear.
    Figure 1. Message displayed for scripting error
    Dynamic action error message
    Limit dynamic inputs type inputs to 40 input values
    A dynamic inputs type input can only render a certain number of inputs before the JSON object becomes to too big to store in memory. Limiting your dynamic inputs to 40 input values minimizes the chances that you will run out of memory and experience unexpected behaviors such as rendering errors or data truncation.
    Limit JSON output to 5000 array items for dynamic templates and dynamic choices
    Dynamic choice and dynamic template inputs can only display up to 5000 array items. A dynamic choice can only display up to 5000 choice list options, and a dynamic template can only display up to 5000 field template values. If your data gathering action collects data for a dynamic template or a dynamic choice, restrict the maximum number of array items it returns to 5000. The 5000 array items limit prevents the instance from having performance issues when rendering the choices or field values.