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Use Hidden Fields to Pass Data From the URL to Your Projects
Use Hidden Fields to Pass Data From the URL to Your Projects

Save Data From the URL, Pipe Values to the Text and Prefill or Hide Personal Data Fields

Adrian avatar
Written by Adrian
Updated over a week ago

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Hidden Fields are a smart way to enhance the functionality and behavior of your projects. You can try them out and see how they work in draft projects, regardless of the plan you're in.

What Are Hidden Fields and How Do They Work?

Hidden fields are question/answer pairs that are saved by adding them to your URL.

It is usually used if you already have this data from your contacts and want to show it in the text, prefill a personal data field or save it without them realizing that it was there in the first place. This is what it looks like:

Or when embedded:

How Hidden Fields Can Be Used

  • Personalize messages on any page using Answer Piping,

  • Save predefined used URL parameters like utm_source, fbclid etc,

  • Pre-fill or hide personal data if you already have that information,

  • Added to calculator formulas, which can then be used to set the payment amount,

  • Link two projects or other tools together using data in buttons or redirects and populate hidden fields in the second project.

Try out the hidden fields feature and learn to use it interactively:

How to Setup Hidden Fields

To start using hidden fields, open your project in the editor, click on the cogwheel icon in the top right corner to open the dropdown menu, then click on "Hidden Fields".

Click the "Add hidden field" button and choose if you want to create a predefined contact data info field or a custom parameter.

  • Custom parameters - Can be defined freely and save its value if they are passed through the URL. They are also available in Answer Piping once created. If you want to create UTM parameters for example, choose this option.

  • Functional fields (Start with page) - Allows you to predefine the first page a participant sees.

  • Contact data fields - These are predefined fields that work the same way as the Contact Form content element. If the field is present in the URL you can choose to pre-fill the field in the Contact Form element or hide it. The "Hidden fields behavior" option can be found in the options of that element. The parameter name is the same for all language settings.

Custom parameters need to be lowercase and are usually separated with underscores. You can customize the title, which will affect how it looks in analytics and reports and you can also add a fallback.

Collected hidden fields show up in your analytics as questions (custom parameters) or as personal data (contact data fields).


Fallbacks are especially useful if you have most of your participants details and you're pre-filling them via hidden fields, but for those cases where you don't have the details, a fallback will be used instead (if you set one).

A good example of this would be, when you're sending out emails to your participants and they start with "Hi (First Name)". If you don't have the participant's first name, but the fallback has been set to "there" then the email will start with "Hi there" instead.

Remote ID

The parameter "remote_id" is a special hidden field because you can use it to save a value without creating the hidden field for it in the first place in the editor.

Good to Know

  • The following should be kept in mind, when prefilling data for the following hidden fields:

    • Gender - The only accepted options are: male, female and not known.

    • Birthday - Only numbers are accepted and they must have the YYYY-MM-DD format.

    • Country - Country codes should be used here.

  • To pass values containing spaces or other special characters in the URL, make sure to encode them before you add them. So the text "I don't know!" encodes to be "I%20don%27t%20know%21" for the URL. You can use online tools like this to encode your strings. %20 is how space is written in a URL (since URLs are not allowed to contain actual spaces).

Hidden Field Parameters in Embed Code

If you are embedding your project, you can pass hidden field data through parameters in the embed code. Simply use data-params in the div section of the embed code to add your parameters:

<div class="involveme_embed" data-project="projectname" data-params="field1=value1,field2=value2"><script src=""></script></div>
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