Validation Rules

Validation rules control what applicants are allowed to enter in a field. Fundament checks these rules when the applicant tries to submit.

Making a field required

The simplest validation is marking a field as required. Applicants cannot submit the form until every required field has a value.

Text length

For text fields, the following can be set:

• Minimum length: the applicant must type at least this many characters
• Maximum length: the applicant cannot type more than this many characters; the field then shows a character counter

The same rule limits the number of selected options in multi-select fields and the number of files in file upload fields.

For example, a form might require a project description of at least 100 characters and no more than 2,000.

Number range

For number fields, the following can be set:

• Minimum value: the entered number must be at or above this value
• Maximum value: the entered number must be at or below this value

Date range

For date fields, a minimum and maximum date can be set. Dates outside the allowed range are rejected.

Age range

For date fields used to capture a date of birth, the resulting age can be required to be within a minimum and maximum. Fundament calculates the age automatically and validates it against the allowed range.

File size and type

For file upload fields, the following can be restricted:

• Maximum file size: files larger than this limit are rejected
• Allowed file types: for example, only PDF or only images

IBAN

For text fields that capture a bank account number, an IBAN check can be enabled. Fundament validates the structure and checksum; spaces and lower case are accepted. Optional additions:

• Restrict countries: for example, only IBANs from Switzerland and Liechtenstein
• Reject QR-IBANs: a QR-IBAN only works with a QR-bill and cannot be used for a regular transfer

The error message tells the applicant what to fix first: «Invalid IBAN», «Only IBANs from: …», or «QR-IBAN not allowed. Please use the account’s IBAN.»

Compare against another field (percent)

For number fields, the entered value can be required to be a certain percentage of another field. For example: the applicant’s own contribution must be between 10 % and 50 % of the total budget.

Repeater entries (percent threshold)

Inside a repeater, a certain percentage of entries can be required to satisfy a validation rule. For example: at least 80 % of listed team members must provide a valid email address.

Validation feedback

When an applicant enters something that fails a validation rule, they see a clear error message at the field. The error messages can be customized per rule and language; without a custom text, Fundament uses a default message. The form can only be submitted once all rules are met. Hints from the AI check are separate: they never block submission.