Control which questions are mandatory and how answers are validated.
Making a field required
Toggle the Required switch on any block to make it mandatory. Required fields show a red asterisk (*) next to the question. The form cannot be submitted until all required fields are filled in.
Built-in validation
Some block types have automatic validation:
- - Email — Must be a valid email format (e.g. user@example.com)
- - Phone — Must contain only digits, spaces, dashes, parentheses, and the + symbol
- - File Upload — Enforces the 5MB size limit and allowed file types (PDF, DOC, DOCX, PNG, JPG, JPEG, GIF, WEBP)
- - Rating — Must select a value if required
Validation errors
When a respondent tries to submit with invalid or missing fields:
- The form scrolls to the first error
- Invalid fields are highlighted with a red border
- An error message appears below each invalid field explaining what's wrong
- The submit button shows a loading state, then returns to normal
Tips
- - Mark the most important fields as required, but don't overdo it — requiring every field can frustrate respondents
- - Use block descriptions to explain what format you expect (e.g. "Enter your phone number including country code")
- - Email validation only checks format, not whether the address actually exists