Skip to Content
Lead FormsQuery Parameters

Query Parameters for Prefill

Each form field can be linked to a query parameter in the field settings. This lets you automatically fill form fields from URL query strings.

Why use query parameters

Query parameters enable:

  • Source tracking: know which campaign or channel sent the visitor by passing a source ID
  • User prefill: pre-populate known user data (email, phone) when sending traffic from your own database or CRM
  • Multi-step continuity: pass data between pages so visitors don’t re-enter information
  • A/B testing: vary which field names are used to segment behavior

How to set it up

  1. Select a field inside the form
  2. In Field settings, scroll to Query parameter
  3. Enter the parameter name, e.g., email, utm_source, lead_id
  4. Save the field

Now, when someone visits the page with ?email=user@example.com&utm_source=linkedin, those fields will be pre-filled.

Understanding parameter mapping

The query parameter name on each field tells ResultFly which URL parameter to read for that specific field.

One parameter per field (common case)

For example, if your form has:

  • Email field with query parameter email
  • Hidden field (source tracking) with query parameter utm_source
  • Lead ID field with query parameter lead_id

Then the URL ?email=john@company.com&utm_source=linkedin&lead_id=42056 will automatically:

  • Fill the email field with john@company.com
  • Fill the hidden field with linkedin
  • Fill the lead ID field with 42056

Each field watches for its own parameter name, so you can pass multiple pieces of data in one URL and they’ll land in the right fields.

Using the same parameter for multiple fields

Query parameter names don’t have to be unique within a form. If multiple fields share the same query parameter name, they will all be filled with the same value.

This is useful when you want to:

  • Fill the same data into different format versions of the same field (e.g., a visible email field and a hidden email backup)
  • Replicate data across related fields for specific workflows
  • Simplify URL construction when the same value should populate multiple places

For example, if both a visible email field and a hidden email tracking field use the query parameter email, the URL ?email=john@company.com will fill both fields with the same email address.

Examples

Simple prefill

A campaign URL with prefill:

https://resultfly.com/campaign/123?email=john@company.com&utm_source=email_newsletter

CRM/database integration

When sending traffic from your CRM or internal database:

https://resultfly.com/campaign/123?email=prospect@company.com&lead_id=CRM-12345&company=Acme+Corp

All three fields fill automatically, reducing friction and improving data quality through reduced re-entry.

Building a FormMulti-Step Forms