Learn how to use URL parameters, UTM parameters, and hidden fields to transfer data automatically and make your forms more efficient.
URL parameters
URL parameters (also called query parameters) let you pass information directly to a website or funnel through a URL.
They are added to the end of a URL and consist of key-value pairs. The field name and its value are separated by an equals sign (=). Multiple parameters can be connected with an ampersand (&).
A URL parameter can be used, for example, to automatically pass data such as a name, a campaign, or other information to a form.
Example: Imagine you have a page with a contact form. The form contains two fields:
First name
Last name
The original URL of your form page might look like this, for example:
https://form-example.com/
A URL parameter is made up of several components:
The question mark (
?) indicates that a URL parameter is beginning.fnameis the name of the field to be filled in.The equals sign (
=) connects the field to the value being passed.Johnis the value entered into the field.
If you want to pass several fields at once, you can add more parameters with an ampersand (&).
Example: https://form-example.com/?fname=John&lname=Doe
In this example:
the fname field is filled with "John"
the lname field is filled with "Doe"
This lets you, for example, create personalized forms or automatically pass information from other tools, campaigns, or ads to Onepage.
📌 Please note: If you also want the fields to be filled in automatically, feel free to take a look at the following guide: Automatically filling in form fields
UTM parameters
UTM parameters are special URL parameters used in online marketing to better track where visitors and leads come from.
They help you find out which campaign, platform, or ad brought a visitor to your page. This way you can later analyze which marketing activities are successful.
UTM parameters are added to the end of a URL and transmitted to your page in the background. While your visitors do see this information in the URL, they don't have to fill in any additional fields in your form.
The five most important UTM parameters are:
utm_source → Where does the visitor come from? (e.g. Google, Facebook, newsletter)
utm_medium → Which channel does the visitor come through? (e.g. ad, email, social media)
utm_campaign → Which campaign does the visit belong to?
utm_term → Which search term was used? (often used with search ads)
utm_content → Which ad or link was clicked?
Example: You run a Facebook ad for a free consultation.
Your normal URL is:
https://form-example.com/
With UTM parameters, the URL could look like this:
https://form-example.com/?utm_source=facebook&utm_medium=paid&utm_campaign=consultation2026
When a visitor reaches your page through this ad and fills in a form, the UTM information is automatically stored with the lead.
For ads on platforms like Meta or Google Ads, these parameters are added automatically. No visible form fields are needed; the information is captured in the background.
After a lead has submitted your form, you can view the transmitted URL and UTM parameters in the Lead info in the CRM. To do so, click the relevant lead in the CRM to bring up the stored information.
📌 Please note: Standard UTM parameters (utm_source, utm_medium, utm_campaign, and utm_content) are stored automatically in the CRM on the relevant lead. No additional field is needed for this.
However, if you want to pass the UTM parameters to an external integration or email notifications, you need to create a separate hidden field in the form for each parameter you want and link it accordingly to the respective UTM parameter.
Hidden fields
Hidden fields are special form fields you can add to your forms to automatically capture additional information.
Unlike normal form fields, hidden fields are not visible to visitors on your page. The values are passed to the form in the background via URL parameters or can be pre-filled with a default value.
You can add hidden fields to your form by clicking the blue + icon on the form, switching to the "Form Elements" tab, and selecting the "Hidden field" element.
After you've added a hidden field and click it, three settings are available:
1. Query parameter name
The query parameter name defines the name under which the field is addressed via a URL parameter and filled with a value.
If you use firstname as the query parameter name, for example, you can pass the value through the URL:
https://your-website.com/?firstname=max
The value "Max" is then automatically applied to the hidden field.
📌 Please note: The "query parameter name" must match the name in the URL parameter exactly for the transfer to work.
2. Query parameter default value
The query parameter default value is used when no value is passed via a URL parameter.
Example:
Call with parameter: https://your-website.com/?campaign=summeroffer
→ The hidden field receives the value "Summeroffer"
Call without parameter: https://your-website.com/
→ The hidden field receives the stored query parameter default value.
This way you can make sure a value is stored even when visitors access your page directly or the parameter is missing.
3. Internal name
The internal name is used to identify the hidden field internally and is shown in your CRM. Just click the relevant lead to see it.
It helps you assign stored information more easily. Visitors to your page don't see this label.
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