Using Hidden Field Presets

What are presets in hidden fields?

Hidden fields let you capture data alongside a form submission without showing anything to the visitor.

Presets are pre-built values that Growform fills in automatically when the form loads - items like the page URL, ad-tracking cookies, or a unique ID for the submission.

Use them to:

Track which page or campaign a lead came from
Grab conversion data to be sent back to ad platforms (Facebook, Google, TikTok)
Tag submissions with form identifiers, timestamps, or unique IDs for your CRM

You don't need to write any code or pass values via URL - Growform reads the relevant data from the page the form is embedded on and writes it into the hidden field.

Configuring presets

Add a Hidden field to your form.
In the field's settings, switch the hidden field type to "Value from preset"
Choose the preset you want from the dropdown.
Give the hidden field a sensible name - this is the key your integrations and webhooks will see.

That's it. The value is resolved automatically when the form loads, and is included in every submission.

Reference guide - all presets

Full page URL

Captures the complete URL of the page the form is embedded on, including the query string. For example, the full URL might be "https://example.com/lp?utm_source=google".
Useful for attribution when you need the full URL - including UTM tags - preserved as a single value.

Page path

Captures only the path portion of the landing page (e.g. /lp).
Useful when you want to group submissions by page without query-string noise.

Page domain

Captures just the domain of the landing page (e.g. example.com).
Useful if the same form is embedded across multiple sites and you need to know which one a lead came from.

Referrer URL

Captures the URL the visitor came from before landing on your page, when the browser provides it.
Most modern browsers only share the domain of the referrer (e.g. google.com), not the full URL - this is a browser privacy feature.
The value will be empty if the visitor came directly, opened the page from a bookmark, or arrived from a source that strips the referrer.

Facebook pixel (fbp)

Captures the _fbp cookie set by the Facebook Pixel on your landing page.
Can be used for conversion tracking via the Conversions API (CAPI).
Will be empty if the Facebook Pixel isn't installed on the page, or if the visitor has blocked cookies.

Facebook click ID (fbc)

Captures the _fbc cookie set when a visitor arrives via a Facebook ad (it contains the fbclid from the ad URL).
Used for click attribution in Facebook Ads.
Fallback behaviour: if
- a.) the _fbc cookie is not present and;
- b.) fbclid is present in the URL...
- Growform will construct a fbc value using the fbclid and current timestamp, according to Facebook's best practices.
Value will be empty if the visitor didn't arrive from a Facebook ad and the cookie isn't set.

Form name

Captures the name of this form as set in Growform.
Useful for tagging submissions when the same destination (CRM, webhook, spreadsheet) receives data from multiple forms.

Form ID

Captures the unique internal ID of the form.
More reliable than the form name for routing or matching, since the name can change but the ID is permanent.

Google Click ID (gclid)

Captures the gclid parameter set when a visitor arrives via a Google Ad.
Used for Google Ads conversion tracking and uploading offline conversions.
Will be empty if the visitor didn't come from a Google ad or if tracking is blcoked

Google Analytics client ID

Captures the Google Analytics client ID from the _ga cookie.
Used with the GA4 Measurement Protocol to send server-side events that tie back to the same visitor session in Analytics.
Will be empty if Google Analytics isn't installed on the page or the cookie hasn't been set yet.

TikTok pixel (ttp)

Captures the _ttp cookie set by the TikTok Pixel.
Used for TikTok Ads conversion tracking via the Events API.
Will be empty if the TikTok Pixel isn't installed or cookies are blocked.

TikTok click ID (ttclid)

Captures the ttclid parameter set when a visitor arrives via a TikTok ad.
Used for click attribution in TikTok Ads.
Will be empty if the visitor didn't arrive from a TikTok ad.

Unique ID

Generates a time-encoded unique identifier when the form loads.
The same ID is included with the submission and can be used as a deduplication key - for example, as the event_id for Facebook CAPI to prevent the same conversion being counted twice when fired from both the browser pixel and server-side.
Also useful as an idempotency key when posting to a CRM.

Timestamp

Captures an ISO 8601 timestamp at the moment the form loads (e.g. 2026-05-07T14:23:11.000Z).
Note: this is the form load time, not the submission time - useful if you want to measure how long a visitor spent filling in the form.