Dynamic inputs

  • Release version: Zurich
  • Updated July 31, 2025
  • 5 minutes to read
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    Summary of Dynamic inputs

    Dynamic inputs in ServiceNow enable you to generate a list of input values each time an action is configured in a flow within Flow Designer. These inputs can dynamically display related action inputs, record fields, or choice list options, enhancing flexibility and responsiveness during flow design. Dynamic inputs require theFlow Designer - Introspectionplugin and are not available in the base system. They are particularly useful for integrating with third-party systems and adapting to changing data structures without modifying the action itself.

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    Types of Dynamic Inputs

    • Dynamic Choice: Generates a list of choice values for selection.
    • Dynamic Inputs: Allows adding arbitrary inputs to an action dynamically.
    • Dynamic Template: Retrieves fields from a selected record type, dynamically adapting to changes in the source table.

    How to Use Dynamic Inputs

    Using dynamic inputs involves three key steps:

    • Create a data gathering action that collects dynamic data, typically through REST calls or scripts returning JSON.
    • Create an action with a dynamic input configured to invoke the data gathering action.
    • Add this action to a flow and configure it using the dynamically gathered data.

    Data Gathering Actions

    Data gathering actions serve as providers of dynamic data for inputs and are not added directly to flows. They must output JSON-formatted data with a data property and adhere to specific constraints:

    • One JSON output named output derived from a script step.
    • Limit returned items to 5000 for dynamic choices and templates to avoid performance issues.
    • Timeout default is 300 seconds, adjustable via system property snflowdesigner.syncactionexecutiontimeoutinseconds.

    Supported Data Types

    Dynamic inputs support various ServiceNow AI Platform data types including Choice, Datetime, Decimal, Email, HTML, Integer, Password2, Reference, and String. This flexibility allows you to customize input fields to match your specific data requirements.

    Best Practices and Guidelines

    • Consider dynamic inputs for third-party integrations to fetch endpoint-specific data dynamically.
    • Manage timeouts carefully: Longer timeouts can be set but avoid them in interactive flows to maintain responsiveness.
    • Handle scripting errors: Scripts powering dynamic inputs can fail, so monitor for errors that may prevent input population.
    • Limit dynamic inputs to 40 input values to prevent memory overload and rendering issues.
    • Restrict JSON output to 5000 items for dynamic templates and choices to maintain performance.

    Getting Started

    To implement dynamic inputs, begin by creating sample data gathering actions for each dynamic input type (choice, template, inputs). Configure corresponding actions to use these data gathering actions, then add them to your flows to enable dynamic configuration during flow design.

    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 reference.

    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.