SourceTag

Form Setup

Set up SourceTag with Paperform

Paperform supports hidden fields and URL-based prefills. You add hidden fields in the form editor, then embed the form on your site. SourceTag detects the embedded form and populates the fields with attribution data.

What you need

  • SourceTag installed on your website
  • A Paperform account
  • The form embedded on your site (not using the hosted Paperform URL)

Step 1: Open your form in the Paperform editor

Log in to Paperform and open your form in the editor.

[IMAGE: Screenshot of Paperform form editor]

Step 2: Add hidden fields

  1. In the form editor, click the + button to add a new field
  2. Choose Hidden from the field type list
  3. Give it a name that matches the SourceTag field name (e.g. st_fc_channel)
  4. Repeat for each SourceTag field

In Paperform, hidden fields do not appear to visitors. They only show up in the editor and in submission data.

[IMAGE: Screenshot of Paperform editor showing a hidden field being added]

Core fields (add these)

Add a hidden field for each of the following:

  • st_fc_channel
  • st_fc_detail_1
  • st_fc_detail_2
  • st_fc_detail_3
  • st_fc_detail_4
  • st_lc_channel
  • st_lc_detail_1
  • st_lc_detail_2
  • st_lc_detail_3
  • st_lc_detail_4
  • st_fc_landing_page
  • st_lc_landing_page

Optional extended fields

If you have enabled extended field groups in your SourceTag dashboard, also add:

  • st_fc_click_id and st_lc_click_id (click IDs)
  • st_visits (visit count)
  • st_days_to_convert (days since first visit)
  • st_device (device type)

Step 3: Set the field key

For each hidden field:

  1. Click on the hidden field
  2. In the field settings, find the Custom Key or Field Key setting
  3. Set it to the SourceTag field name exactly (e.g. st_fc_channel)
  4. Leave the prefill/default value empty

The custom key controls the HTML name attribute when the form is rendered. This is what SourceTag uses to find the field.

[IMAGE: Screenshot of Paperform hidden field settings showing the custom key]

Step 4: Embed on your site

  1. In Paperform, go to Share > Embed
  2. Choose the Standard embed (JavaScript embed) option
  3. Copy the embed code and paste it onto your page
<!-- Your site already has SourceTag -->
<script src="https://cdn.sourcetag.io/scripts/YOUR_ID/st.js" async></script>

<!-- Paperform embed -->
<div data-paperform-id="YOUR_FORM_SLUG"></div>
<script>(function() { var script = document.createElement('script'); script.src = "https://paperform.co/__embed.min.js"; document.body.appendChild(script); })()</script>

The page must have the SourceTag script installed. If you use a direct link to the Paperform hosted URL, SourceTag will not be able to populate the fields.

[IMAGE: Screenshot of Paperform embed options]

Step 5: Test

Visit the page with UTM parameters:

?utm_source=test&utm_medium=cpc&utm_campaign=paperform-test

Submit the form. In Paperform, go to Submissions and check the test entry. The hidden fields should contain your attribution data.

[IMAGE: Screenshot of Paperform submission showing populated hidden fields]

Tips

  • Custom keys in Paperform are case-sensitive. Copy the field names from the Fields page in your SourceTag dashboard.
  • Paperform’s integrations (Zapier, webhooks, Google Sheets, etc.) include hidden field values in the submission data.
  • If your form has calculation or conditional logic fields, hidden fields work independently of those and will not interfere.
  • If hidden fields come through empty, check that your form is embedded using the standard embed (not an iframe) and that the custom key matches the SourceTag field name exactly.