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Hidden fields & URL prefill

Capture UTM parameters from the form link invisibly, and prefill visible fields for known respondents.

A hidden field is a question respondents never see. Instead of being answered, it captures a query parameter from the link the respondent opened, and the value lands in your results and exports like any other answer. Use it to record where a submission came from: a campaign, a source, or your own user id.

How it works

  1. Add a hidden field

    Insert it from the slash menu like any block and give it a name, say utm_source. The name is the query parameter it captures.

  2. Add the parameter to your link

    Share the form as formbear.app/f/abc123?utm_source=newsletter. The field's settings panel shows a copyable example link.

  3. Read the value in your results

    Every submission from that link records newsletter under the field, in the responses table, the summary, and CSV exports.

Prefill visible fields

The same link mechanic fills visiblefields with a starting value the respondent can still edit. A parameter whose name matches a question's label (case-insensitively) becomes that field's default:

code
https://formbear.app/f/[email protected]&Color=Blue
Prefills the Email question and selects the Blue option.
  • Choice questions (select, multi select, dropdown) match an option by its label; multi select takes several values separated by commas or repeated parameters.
  • Dates expect YYYY-MM-DD; numbers and ratings must fit the field's bounds. A value that doesn't fit is simply ignored, so a bad link shows an empty field, never a broken one.
  • File upload questions can't be prefilled.

Good to know

  • Parameter names match the field name case-insensitively, so ?UTM_Source=x still lands in utm_source.
  • Hidden fields are never required: a link without the parameter submits normally, the field just stays empty.
  • Each hidden field needs a name of its own: not shared with another hidden field or a question's label (the parameter would fill both), and not preview or transparent, which the form page uses itself. Publishing checks all of this for you.
  • Hidden fields never appear to respondents, in any layout: guided forms skip them when splitting pages.