Hidden Fields & URL Pre-fill

Hidden Fields & URL Pre-fill

Hidden fields capture data without showing anything to the respondent. Use them to track traffic sources, pass in user IDs, or pre-fill values from your system.

Adding a Hidden Field

1. In the form editor, add a Hidden field from the field palette
2. Set the field slug (this becomes the URL parameter name)
3. Optionally set a default value

URL Pre-fill

Pass values via URL query parameters:

https://pickedsmart.com/f/my-form?source=newsletter&campaign=spring2026

If your form has hidden fields with slugs source and campaign, they will be automatically populated with the URL values.

Use Cases

• UTM tracking - capture utm_source, utm_medium, utm_campaign
• User identification - pass in a customer ID from your app
• A/B testing - track which variant a respondent came from
• CRM integration - pre-fill with data from your CRM via webhooks

Viewing Hidden Field Data

Hidden field values appear in the response detail view and are included in CSV/JSON exports. They can also be sent via webhooks for downstream processing.