Field Validation

Validation ensures that entered data meets your criteria before submission.

Automatic Validation

Some modules have built-in validation:

Module	Automatic Validation
Email	Valid email format
Phone	Valid phone format
IBAN	IBAN check key
Date	Valid date
Number	Numeric value

Required Field

The most common parameter:

1. Open the module settings
2. Enable "Required"
3. The user cannot continue without filling it

Visual Indicator

Required fields are marked with a red asterisk (*).

Validation Rules

Text Length

For text fields:

Parameter	Description
Minimum	Minimum number of characters
Maximum	Maximum number of characters

Example: French postal code

• Minimum: 5
• Maximum: 5

Numeric Values

For number fields:

Parameter	Description
Minimum	Minimum accepted value
Maximum	Maximum accepted value
Decimals	Number of digits after decimal point

Example: Percentage

• Minimum: 0
• Maximum: 100
• Decimals: 2

Dates

For date fields:

Parameter	Description
Minimum date	Cannot be before
Maximum date	Cannot be after
Allowed days	Exclude weekends, holidays

Example: Appointment date

• Minimum: today
• Maximum: +30 days
• Exclude: Saturdays, Sundays

Files

For uploads:

Parameter	Description
Accepted types	Allowed extensions
Maximum size	In MB
Number of files	Min/max for multiple upload

Example: ID document

• Types: PDF, JPG, PNG
• Max size: 10 MB

Regular Expression (Regex)

For advanced custom validations:

Common Examples

French postal code:

^[0-9]{5}$

SIRET number:

^[0-9]{14}$

License plate:

^[A-Z]{2}-[0-9]{3}-[A-Z]{2}$

Configuration

1. Open the text module settings
2. In "Advanced validation", add the expression
3. Define the custom error message

Error Messages

Default Messages

Formulr displays appropriate messages:

• "This field is required"
• "The email address is not valid"
• "The value must be between X and Y"

Custom Messages

For each rule, you can customize the message:

1. In validation settings
2. "Error message" field
3. Enter your text

Example:

"Please enter a French postal code with 5 digits"

Server-side Validation

In addition to browser-side validation, Formulr verifies:

• All rules at submission
• Integrity of uploaded files
• Data consistency

Security

Don't rely solely on client-side validation. Server validation is always enforced.

Best Practices

1. Be Explicit

• Indicate the expected format in the placeholder
• Use help text for complex cases

2. Clear Messages

• Explain how to correct the error
• Avoid technical jargon

3. Don't Over-validate

• Accept common formats
• Avoid overly restrictive rules

4. Test

• Try boundary values
• Verify error cases

Next Steps

• Module Types - All available modules
• Conditional Logic - Dynamic display