Making a field required
Toggle Required on any field to prevent form submission unless that field has a value. Filla checks required fields before submission and shows an error on any field that’s empty. What “empty” means depends on the field type:- Text fields: empty string or whitespace only
- Number fields: no value entered
- Select fields: no option selected
- File upload: no files uploaded
- Linked record: no records selected
Custom validation rules
Beyond required, you can add custom validation rules to any field. Rules are built with the same filter builder used for conditional logic. They let you express constraints like:- “This number must be greater than 0”
- “This text must contain the word ‘http’”
- “This date must be in the future”
Add a rule
Click Add rule in the validation conditions builder. Select an operator and enter a value. Add multiple conditions with AND/OR logic.
Validation settings
| Setting | Description |
|---|---|
| Required | Respondent must fill in this field before submitting. |
| Custom validation rules | Filter-based conditions the field’s value must satisfy. |
| Validation error message | The message shown when a custom rule fails. Use this to give clear, specific guidance. |
Reject duplicate values
Enable Reject duplicate values to prevent a value that already exists in the Airtable table from being submitted again. See Reject duplicates for details.How validation order works
Filla runs validations in this order:- Required check (is the field empty?)
- Min/max character length (text fields)
- Domain restrictions (email fields)
- Phone format (phone fields)
- Date range (date/datetime fields)
- Number range (number/currency/percent fields)
- Max selections (multiple select fields)
- Linked record count limits
- Attachment limits
- Custom validation rules
Common questions
Can I make a field conditionally required?
Can I make a field conditionally required?
Not with a direct toggle, but you can combine conditional visibility with required. If a field is only shown when certain conditions are met, and it’s marked required, the required check only applies when the field is visible.
Can I write a validation rule that references another field?
Can I write a validation rule that references another field?
Custom validation rules evaluate the field’s own value against a static condition. They cannot directly compare one field to another. Use conditional visibility or a formula field in Airtable for cross-field dependencies.
Is validation enforced server-side?
Is validation enforced server-side?
Yes. Filla runs validation on the server when the form is submitted, not just in the browser. This means validation cannot be bypassed by disabling JavaScript.