Hidden fields have many uses. For example, they can be used to:

  • Identify what marketing campaign a lead came from

  • Capture additional information about leads you already have an email address for (without re-asking for their email address).

Hidden fields capture information from a URL parameter and then include it with a form submission as if the user had filled out a form field.

For example, if you want to know which marketing campaigns your leads are coming from, you could send your leads to a URL with the campaign name in the URL, such as:


If your form had a hidden field called 'campaign' it would capture the value (twitter) from the URL and populate a hidden field, submitting it alongside the other information in your form.

Example 1: Progressive profiling

Progressive profiling is when you capture additional information about a lead over time.

Let's say you have a whitepaper form and a webinar form. If someone has already given you their email address by submitting the whitepaper form, you probably don't want to ask for their email address again when they fill out your webinar form.

As you can see in the example below, the email address appears in the URL as a parameter. Despite the email address not being entered in the form, it is being submitted along with the data that has been entered.

Example 2: Tracking the lead source

If you're running a marketing campaign, you probably want to know which leads were generated from that campaign. You can attach this information to each form submission using hidden fields.

If you're using Google's UTM tracking, your landing page URL will look something like this.


In Leadformly, you could create hidden fields for:

  • utm_source

  • utm_medium

  • utm_campaign

Now, every time a lead submits your form from this URL you will know precisely which campaign to attribute them to.

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