Languages (i18n)

Write the form once in its default language, then add translations. Anything not translated falls back to the default language.

"i18n": {
  "defaultLanguage": "en",
  "languages": ["en", "es", "fr"],
  "detect": true,
  "switcher": "flags",
  "translations": {
    "es": {
      "title": "Contáctanos",
      "settings.submitButtonText": "Enviar",
      "field.name.label": "Tu nombre",
      "field.plan.option.free": "Gratis",
      "ui.submit": "Mandar"
    }
  }
}

• Which language is shown: the language prop if set (it also hides the switcher); else the visitor's choice in the switcher; else the browser language (navigator.languages, detect is on by default) when it matches one of languages (pt-BR matches pt); else defaultLanguage.
• Switcher: "none" (default), "flags" or "dropdown": a language selector at the top of the form. Flags are emoji, so on Windows they show as letters.
• Keys: title, description, settings.<name>, settings.sidebarHeader.<title|subtitle>, settings.sidebarActions.<index>.label, and field.<field id>.<label|helpText|tooltip|placeholder|content|checkboxLabel|config.minLabel|config.maxLabel|config.unit>, field.<id>.option.<option value>, field.<id>.<optionDesc|optionBadge|optionHelp|optionLink|optionAlt>.<option value>, field.<id>.validation.<rule name> (a custom error message). The builder's Translate tab lists them all.
• Built-in texts (buttons, step counter, upload text, default error messages, country names) are translated for en es fr de it pt nl pl ca da and can be overridden per language with ui.* / validation.* keys (see BUILT_IN_UI in src/utils/i18n.ts). Other languages use English for these unless you provide them. This works for the default language too, so a single-language form can reword them: "translations": { "en": { "ui.step": "Stage {current} of {total}" } }. Country names use the browser's Intl.DisplayNames.
• ar, he and fa set dir="rtl" on the form.

<re-form-generator language="es"></re-form-generator>   <!-- force a language -->
<script>
  form.addEventListener('languageChanged', e => console.log(e.detail.language));
  form.setLanguage('fr');                                 // switch from your own UI
</script>