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Documentation Index

Fetch the complete documentation index at: https://filla.io/docs/llms.txt

Use this file to discover all available pages before exploring further.

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What prefilling does

Prefilling loads a field with a value before the respondent interacts with it. Respondents can change the pre-filled value unless the field is also set to read-only. There are three ways to prefill a field:
  1. Default value: set a static or dynamic value in the field settings
  2. URL parameters: pass values in the form URL when you share or embed it
  3. Auto-fill today’s date (date / date-time fields only): stamp today’s date when the form loads

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Default values

Most editable field types have a Default value setting inside the Label & description section of the field settings panel. This value loads when the form opens.

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Static defaults

Enter a fixed value, for example a default country (United States) or a default status (Pending). Every respondent sees the same pre-filled value.

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Dynamic defaults with variable references

Type @ in the default value field to open the variable picker. Select any field that has already appeared in the form. The default value resolves dynamically based on what the respondent entered in that earlier field. Example: A “Shipping address” field could default to the value from a “Billing address” field. If the respondent changes the billing address first, the shipping address pre-fills to match. The respondent can still override it.

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Auto-fill today’s date (date fields only)

Date and Date Time fields have a dedicated Auto-fill today’s date toggle that pre-fills the field with the current date when the form loads. No default value, no URL parameter, no respondent action needed. Use it for “Submitted on”, “Report date”, “Date of inspection” — fields where today is almost always the right answer. Works with read-only. Combine Auto-fill today’s date with Read-only to auto-stamp the submission date — the field fills automatically and the respondent cannot edit it. This is the canonical pattern for guaranteed-accurate timestamps. See Date fields for the full setting reference.

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Prefilling via URL parameters

You can pass values as URL query parameters when sharing or embedding your form. Use the prefill_ prefix followed by the Airtable field name (not the field ID): 
?prefill_Name=Jane+Smith&prefill_Email=jane@example.com
URL prefill works automatically on any field whose Airtable name matches the parameter. There is no toggle to enable it and no configuration step — share or embed the URL with the parameters and the matching fields fill in on load.
Prefill only resolves field names, not field IDs. prefill_fldAbc123 is silently ignored — always use the human-readable name from Airtable.
Common uses:
  • Pre-filling a respondent’s name and email when sending a link from your CRM
  • Pre-filling a project or account ID when embedding a form in your app
  • Tracking source by pre-filling a campaign field
See Prefilling fields via URL for the full syntax and field type support.

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Read-only prefilled fields

Enable Read-only on a field to display a pre-filled value that respondents cannot change. The value can come from any source:
  • A Default value set in the field settings
  • A URL parameter (?prefill_FieldName=value) — read directly into the field, no extra configuration needed
  • The existing record value in edit mode
  • Auto-fill today’s date on a date / date-time field — fills with the current date the moment the form loads, no URL needed
You don’t need to tie these together — a read-only field simply displays whatever value is present. There’s no {{prefill_FieldName}} syntax; URL parameters populate fields automatically whether they’re read-only or not.

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Common questions

Default values support @ variable references to other form fields, not Airtable formulas. If you need a calculated default, set up a formula field in Airtable and use that as a prefill source in edit mode, or use the URL parameter approach to pass a computed value from your application.
The field appears with the value already in it. There is no visual indicator that it was pre-filled vs manually entered.
The URL parameter takes precedence over the default value setting.
Yes. Pass the exact option value (case-sensitive) as the URL parameter. If the value doesn’t match an existing option, the field stays empty.