Validation

Formerie validates submitted values on the server. SDK or browser-side checks can improve user experience, but final submission remains authoritative.

Field Paths

Nested fields use dot and bracket paths:

Text

contact.email
guests[0].email
guests[1].name

Validation responses use these paths in both error.fields and error.issues.

Multiple Issues Per Field

A single field can return multiple issues. UI code should preserve all issues and choose whether to show the first issue or the full list.

JSON

{
  "path": "contact.email",
  "code": "FIELD_EMAIL_INVALID",
  "message": "Invalid email address.",
  "rule": "email",
  "params": {}
}

Common Field Capabilities

Formerie supports common deterministic validation and normalization patterns:

required fields
string min, max, and exact length
email, URL, phone, UUID, date, time, and date-time checks
allowed values
number bounds and integer requirements
array min, max, and uniqueness checks
nested object fields
server-defined contextual form rules
server-defined conditional visibility rules
trimming, email normalization, case transforms, and safe sanitizers

Hidden fields are skipped by the API and are not included in sanitized values. Use visibility rules for UI display only; delivery, recipients, templates, and provider credentials remain server-managed.

Partial And Step Validation

Use POST https://forms.formerie.com/{workspaceHandle}/{formHandle}/validate or the SDK validate() helper for progressive forms. If you explicitly target the API surface, the equivalent API route is POST /v1/{workspaceHandle}/{formHandle}/validate on https://api.formerie.com.

partial: validate only provided fields.
step: validate fields configured for the named public step.
final submission: validates the full form and remains authoritative.

Partial validation does not persist submissions, verify CAPTCHA tokens, reserve quota, or send email.