Externally provided variables
Capture values passed into flows, even if not collected in questions (also known as hidden fields).
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Capture values passed into flows, even if not collected in questions (also known as hidden fields).
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There are many cases where you might want to pass data into a form that would never be provided by the responder directly, like:
tracking information, such as unique identifiers, account IDs, etc;
configuration variables, which enable or disable certain functionality.
External variables are created in Formsort to capture parameters that are passed into a flow via the URL.
Consult the URL parameters page for more information on the proper format and other details.
If you're familiar with HTML form semantics, this is the equivalent of a <input type="hidden"> field which is part of a form, but not provided by the user.
Much like a variable provided by a user, external variables can be used in variable templating, conditional logic, and in functions for locally-calculated variables.
To use an external variable for URL parameter capture, in the Variables tab, select Externally provided > Add External Variable, and set the name of the expected URL parameter in the Variable name field.
For example, if a user is being directed into your Formsort flow with utm_source as a URL parameter, the URL will look something like this:
https://<YOUR_FLOW_URL>/?utm_source={{example_utm_value}}
In order for Formsort to capture the value of utm_source, you need to create an external variable called utm_source. This variable will automatically store the value of the URL parameter when the flow loads.
Use the Is array option if the field passed into the flow has an array format. For more information on the accepted query parameter convention, see URL parameters.
When the Required field is enabled, two things will happen when the external variable is not passed in to a user session:
A warning will be logged to the browser console during the user session; and
An error field called externalVarIssues will be submitted in the flowLoaded event answer payload. This second point requires having an analytics integration set up.
The externalVarIssues field is an object; see example:
"externalVarIssues":{"ext_var_name":"missing"}
When a flow is loaded in Formsort, any URL parameters that match any variable defined in the flow will be placed into the variables and removed from the URL. To learn more about that, read about getting data in from URL parameters.
If you would like instead for a variable value to remain in the URL, enable Keep in URL if present on load. This might be helpful if you are matching up campaigns on a URL string, and want to keep things like the utm_source consistent across pages.
Anything in the URL will most likely be recorded by any analytics scripts you include in the integrations, so avoid enabling this setting for variables that set personally-identifying information.
Another option is to store answers in cookies. In cases where you are collecting more sensitive information, this might be a better option, since you might not want to pass sensitive information unencrypted via URL. In order to do so, you can enable Read/Write in Cookie option.
Configuring a domain is required to store answers in cookies.
Take care when "start each session as a new responder" is enabled in your Variant Settings, as the setting will remove Formsort-related cookies by default. See the Prevent Editing option below to guard against this.
When a default value is set, if a value is not present when a flow is loaded, the default value will be used.
A common use for this is to define control variables, similar to constants, that govern what parts of a flow are enabled, or function as a setting parameter.
By default, external variables passed in as query parameters can be overridden in the flow. If, for example, zip_code is passed in as a query parameter, but a question then asks the user to enter their zip code to a variable zip_code, the external answer will be replaced by the submitted answer. If you want to ensure external answers passed in as query params cannot be overriden, enable the Prevent Editing? option.
Prevent editing can also be used to persist external variables that are read from/written to cookies, when "start each session as a new responder" is enabled.
Read more about start each session as a new responder here.
External variables are automatically included in answers payload delivery, if they are provided in the URL at flow load. No further configuration is needed once the form is deployed with the update
