increase test coverage

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/web/app/api/v1/client/[environmentId]/environment/lib/data.ts

@@ -86,6 +86,7 @@ export const getEnvironmentStateData = async (environmentId: string): Promise<En
             variables: true,
             type: true,
             showLanguageSwitch: true,
+            autoSelectLanguage: true,
             languages: {
               select: {
                 default: true,

apps/web/app/lib/templates.ts

@@ -4924,6 +4924,7 @@ export const previewSurvey = (projectName: string, t: TFunction): TSurvey => {
     languages: [],
     triggers: [],
     showLanguageSwitch: false,
+    autoSelectLanguage: false,
     followUps: [],
     isBackButtonHidden: false,
     isAutoProgressingEnabled: true,

apps/web/lib/survey/__mock__/survey.mock.ts

@@ -226,6 +226,7 @@ const baseSurveyProperties = {
   },
   isVerifyEmailEnabled: false,
   isSingleResponsePerEmailEnabled: false,
+  autoSelectLanguage: null,
   attributeFilters: [],
   ...commonMockProperties,
 };

apps/web/lib/survey/service.test.ts

@@ -18,6 +18,7 @@ import {
   mockActionClass,
   mockId,
   mockOrganizationOutput,
+  mockSurveyLanguages,
   mockSurveyOutput,
   mockSurveyWithLogic,
   mockTransformedSurveyOutput,
@@ -615,6 +616,33 @@ describe("Tests for createSurvey", () => {
     languages: [],
   } as TSurveyCreateInput;
 
+  const getMultiLanguageCreateSurveyInput = (): TSurveyCreateInput =>
+    ({
+      ...mockCreateSurveyInput,
+      welcomeCard: {
+        ...mockCreateSurveyInput.welcomeCard,
+        headline: { default: "Welcome", de: "Willkommen" },
+      },
+      questions: mockCreateSurveyInput.questions.map((question) => {
+        if ("choices" in question && Array.isArray(question.choices)) {
+          return {
+            ...question,
+            headline: { ...question.headline, de: question.headline.default },
+            choices: question.choices.map((choice) => ({
+              ...choice,
+              label: { ...choice.label, de: choice.label.default },
+            })),
+          };
+        }
+
+        return {
+          ...question,
+          headline: { ...question.headline, de: question.headline.default },
+        };
+      }),
+      languages: mockSurveyLanguages,
+    }) as TSurveyCreateInput;
+
   const mockActionClasses = [
     {
       id: "action-123",
@@ -647,6 +675,45 @@ describe("Tests for createSurvey", () => {
       expect(subscribeOrganizationMembersToSurveyResponses).toHaveBeenCalled();
     });
 
+    test("enables browser language auto-selection by default for new multi-language surveys", async () => {
+      vi.mocked(getOrganizationByEnvironmentId).mockResolvedValueOnce(mockOrganizationOutput);
+      prisma.survey.create.mockResolvedValueOnce({
+        ...mockSurveyOutput,
+      });
+
+      await createSurvey(mockEnvironmentId, {
+        ...getMultiLanguageCreateSurveyInput(),
+      });
+
+      expect(prisma.survey.create).toHaveBeenCalledWith(
+        expect.objectContaining({
+          data: expect.objectContaining({
+            autoSelectLanguage: true,
+          }),
+        })
+      );
+    });
+
+    test("preserves explicit browser language auto-selection setting on create", async () => {
+      vi.mocked(getOrganizationByEnvironmentId).mockResolvedValueOnce(mockOrganizationOutput);
+      prisma.survey.create.mockResolvedValueOnce({
+        ...mockSurveyOutput,
+      });
+
+      await createSurvey(mockEnvironmentId, {
+        ...getMultiLanguageCreateSurveyInput(),
+        autoSelectLanguage: false,
+      });
+
+      expect(prisma.survey.create).toHaveBeenCalledWith(
+        expect.objectContaining({
+          data: expect.objectContaining({
+            autoSelectLanguage: false,
+          }),
+        })
+      );
+    });
+
     test("creates a private segment for app surveys", async () => {
       vi.mocked(getOrganizationByEnvironmentId).mockResolvedValueOnce(mockOrganizationOutput);
       prisma.survey.create.mockResolvedValueOnce({

apps/web/lib/survey/service.ts

@@ -58,6 +58,7 @@ export const selectSurvey = {
   singleUse: true,
   pin: true,
   showLanguageSwitch: true,
+  autoSelectLanguage: true,
   recaptcha: true,
   metadata: true,
   customHeadScripts: true,
@@ -591,9 +592,12 @@ export const createSurvey = async (
   try {
     const { createdBy, languages, ...restSurveyBody } = parsedSurveyBody;
     const actionClasses = await getActionClasses(parsedEnvironmentId);
+    const hasMultipleEnabledLanguages = (languages ?? []).filter((language) => language.enabled).length > 1;
 
     let data: Omit<Prisma.SurveyCreateInput, "environment"> = {
       ...restSurveyBody,
+      autoSelectLanguage:
+        restSurveyBody.autoSelectLanguage ?? (hasMultipleEnabledLanguages ? true : undefined),
       // @ts-expect-error - languages would be undefined in case of empty array
       languages: languages?.length ? languages : undefined,
       triggers: restSurveyBody.triggers

apps/web/lib/utils/locale.test.ts

@@ -2,7 +2,7 @@ import * as nextHeaders from "next/headers";
 import { describe, expect, test, vi } from "vitest";
 import { AVAILABLE_LOCALES, DEFAULT_LOCALE } from "@/lib/constants";
 import { appLanguages } from "@/lib/i18n/utils";
-import { findMatchingLocale } from "./locale";
+import { findMatchingBrowserLanguageCodes, findMatchingLocale } from "./locale";
 
 // Mock the Next.js headers function
 vi.mock("next/headers", () => ({
@@ -36,6 +36,26 @@ describe("locale", () => {
     expect(nextHeaders.headers).toHaveBeenCalled();
   });
 
+  test("ignores Accept-Language quality values when matching locales", async () => {
+    vi.mocked(nextHeaders.headers).mockReturnValue({
+      get: vi.fn().mockReturnValue("de-DE;q=0.9,en-US;q=0.8"),
+    } as any);
+
+    const result = await findMatchingLocale();
+
+    expect(result).toBe("de-DE");
+  });
+
+  test("returns browser language codes without quality values", async () => {
+    vi.mocked(nextHeaders.headers).mockReturnValue({
+      get: vi.fn().mockReturnValue("es-MX,es;q=0.9,en-US;q=0.8"),
+    } as any);
+
+    const result = await findMatchingBrowserLanguageCodes();
+
+    expect(result).toEqual(["es-MX", "es", "en-US"]);
+  });
+
   test("returns normalized match when available", async () => {
     // Assuming we have 'en-US' in AVAILABLE_LOCALES but not 'en-GB'
     const availableLocale = AVAILABLE_LOCALES.find((locale) => locale.startsWith("en-"));

apps/web/lib/utils/locale.ts

@@ -2,11 +2,25 @@ import { headers } from "next/headers";
 import { TUserLocale } from "@formbricks/types/user";
 import { AVAILABLE_LOCALES, DEFAULT_LOCALE } from "@/lib/constants";
 
+const getAcceptedLanguageCodesFromHeader = (acceptLanguage: string | null): string[] => {
+  return (
+    acceptLanguage
+      ?.split(",")
+      .map((language) => language.trim().split(";")[0].trim())
+      .filter(Boolean) ?? []
+  );
+};
+
+export const findMatchingBrowserLanguageCodes = async (): Promise<string[]> => {
+  const headersList = await headers();
+  return getAcceptedLanguageCodesFromHeader(headersList.get("accept-language"));
+};
+
 export const findMatchingLocale = async (): Promise<TUserLocale> => {
   const headersList = await headers();
   const acceptLanguage = headersList.get("accept-language");
-  const userLocales = acceptLanguage?.split(",");
-  if (!userLocales) {
+  const userLocales = getAcceptedLanguageCodesFromHeader(acceptLanguage);
+  if (!userLocales.length) {
     return DEFAULT_LOCALE;
   }
   // First, try to find an exact match without normalization

apps/web/locales/de-DE.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Automatisches Speichern deaktiviert",
         "auto_save_disabled_tooltip": "Ihre Umfrage wird nur im Entwurfsmodus automatisch gespeichert. So wird sichergestellt, dass öffentliche Umfragen nicht unbeabsichtigt aktualisiert werden.",
         "auto_save_on": "Automatisches Speichern an",
+        "auto_select_browser_language": "Browsersprache standardmäßig verwenden",
+        "auto_select_browser_language_description": "Öffnet die Umfrage automatisch in der Browsersprache der befragten Person, wenn diese Sprache aktiv ist. Fällt auf die Standardsprache zurück.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Umfrage automatisch nach <autoCloseInput /> Sekunden nach dem Auslöser schließen, wenn keine Antwort erfolgt.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Schließe die Umfrage automatisch nach einer bestimmten Anzahl von Antworten.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Schließe die Umfrage automatisch, wenn der Benutzer nach einer bestimmten Anzahl von Sekunden nicht antwortet.",

apps/web/locales/en-US.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Auto-save disabled",
         "auto_save_disabled_tooltip": "Your survey is only auto-saved when in draft. This assures public surveys are not unintentionally updated.",
         "auto_save_on": "Auto-save on",
+        "auto_select_browser_language": "Use browser language by default",
+        "auto_select_browser_language_description": "Automatically open the survey in the respondent's browser language when that language is active. Falls back to the default language.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Automatically close survey after <autoCloseInput /> seconds after trigger if no response.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Automatically close the survey after a certain number of responses.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Automatically close the survey if the user does not respond after certain number of seconds.",

apps/web/locales/es-ES.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Guardado automático desactivado",
         "auto_save_disabled_tooltip": "Su encuesta solo se guarda automáticamente cuando está en borrador. Esto asegura que las encuestas públicas no se actualicen involuntariamente.",
         "auto_save_on": "Guardado automático activado",
+        "auto_select_browser_language": "Usar el idioma del navegador por defecto",
+        "auto_select_browser_language_description": "Abre automáticamente la encuesta en el idioma del navegador de la persona encuestada cuando ese idioma está activo. Si no coincide, usa el idioma predeterminado.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Cerrar automáticamente la encuesta después de <autoCloseInput /> segundos tras activarse si no hay respuesta.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Cerrar automáticamente la encuesta después de un cierto número de respuestas.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Cerrar automáticamente la encuesta si el usuario no responde después de cierto número de segundos.",

apps/web/locales/fr-FR.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Sauvegarde automatique désactivée",
         "auto_save_disabled_tooltip": "Votre sondage n'est sauvegardé automatiquement que lorsqu'il est en brouillon. Cela garantit que les sondages publics ne sont pas mis à jour involontairement.",
         "auto_save_on": "Sauvegarde automatique activée",
+        "auto_select_browser_language": "Utiliser la langue du navigateur par défaut",
+        "auto_select_browser_language_description": "Ouvre automatiquement l'enquête dans la langue du navigateur de la personne interrogée lorsque cette langue est active. Sinon, la langue par défaut est utilisée.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Fermer automatiquement le sondage après <autoCloseInput /> secondes si aucune réponse n'est donnée après le déclenchement.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Fermer automatiquement l'enquête après un certain nombre de réponses.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Fermer automatiquement l'enquête si l'utilisateur ne répond pas après un certain nombre de secondes.",

apps/web/locales/hu-HU.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Az automatikus mentés letiltva",
         "auto_save_disabled_tooltip": "A kérdőív csak akkor kerül automatikusan mentésre, ha piszkozatban van. Ez biztosítja, hogy a nyilvános kérdőívek ne legyenek véletlenül frissítve.",
         "auto_save_on": "Automatikus mentés bekapcsolva",
+        "auto_select_browser_language": "A böngésző nyelvének használata alapértelmezésként",
+        "auto_select_browser_language_description": "Automatikusan a válaszadó böngészőnyelvén nyitja meg a kérdőívet, ha ez a nyelv aktív. Ellenkező esetben az alapértelmezett nyelvre vált.",
         "automatically_close_survey_after_n_seconds_if_no_response": "A felmérés automatikus bezárása <autoCloseInput /> másodperc elteltével az aktiválás után, amennyiben nem érkezik válasz.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "A kérdőív automatikus lezárása egy bizonyos számú válasz után.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "A kérdőív automatikus lezárása, ha a felhasználó nem válaszol egy bizonyos másodpercnyi idő után.",

apps/web/locales/ja-JP.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "自動保存が無効",
         "auto_save_disabled_tooltip": "アンケートは下書き状態の時のみ自動保存されます。これにより、公開中のアンケートが意図せず更新されることを防ぎます。",
         "auto_save_on": "自動保存オン",
+        "auto_select_browser_language": "ブラウザーの言語をデフォルトで使用",
+        "auto_select_browser_language_description": "その言語が有効な場合、回答者のブラウザー言語でアンケートを自動的に開きます。一致しない場合はデフォルト言語に戻ります。",
         "automatically_close_survey_after_n_seconds_if_no_response": "トリガー後、反応がない場合は<autoCloseInput />秒後に自動的にアンケートを閉じます。",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "一定の回答数に達した後にフォームを自動的に閉じます。",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "ユーザーが一定秒数応答しない場合、フォームを自動的に閉じます。",

apps/web/locales/nl-NL.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Automatisch opslaan uitgeschakeld",
         "auto_save_disabled_tooltip": "Uw enquête wordt alleen automatisch opgeslagen wanneer deze een concept is. Dit zorgt ervoor dat openbare enquêtes niet onbedoeld worden bijgewerkt.",
         "auto_save_on": "Automatisch opslaan aan",
+        "auto_select_browser_language": "Browsertaal standaard gebruiken",
+        "auto_select_browser_language_description": "Opent de enquête automatisch in de browsertaal van de respondent wanneer die taal actief is. Valt terug op de standaardtaal.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Sluit de enquête automatisch na <autoCloseInput /> seconden na activatie als er geen reactie komt.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Sluit de enquête automatisch af na een bepaald aantal reacties.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Sluit de enquête automatisch af als de gebruiker na een bepaald aantal seconden niet reageert.",

apps/web/locales/pt-BR.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Salvamento automático desativado",
         "auto_save_disabled_tooltip": "Sua pesquisa só é salva automaticamente quando está em rascunho. Isso garante que pesquisas públicas não sejam atualizadas involuntariamente.",
         "auto_save_on": "Salvamento automático ativado",
+        "auto_select_browser_language": "Usar o idioma do navegador por padrão",
+        "auto_select_browser_language_description": "Abre automaticamente a pesquisa no idioma do navegador do respondente quando esse idioma está ativo. Caso contrário, usa o idioma padrão.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Fechar automaticamente a pesquisa após <autoCloseInput /> segundos do acionamento se não houver resposta.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Fechar automaticamente a pesquisa depois de um certo número de respostas.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Feche automaticamente a pesquisa se o usuário não responder depois de alguns segundos.",

apps/web/locales/pt-PT.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Guardar automático desativado",
         "auto_save_disabled_tooltip": "O seu inquérito só é guardado automaticamente quando está em rascunho. Isto garante que os inquéritos públicos não sejam atualizados involuntariamente.",
         "auto_save_on": "Guardar automático ativado",
+        "auto_select_browser_language": "Usar o idioma do navegador por predefinição",
+        "auto_select_browser_language_description": "Abre automaticamente o inquérito no idioma do navegador do respondente quando esse idioma está ativo. Caso contrário, usa o idioma predefinido.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Fechar automaticamente o inquérito após <autoCloseInput /> segundos depois do acionamento se não houver resposta.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Fechar automaticamente o inquérito após um certo número de respostas",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Fechar automaticamente o inquérito se o utilizador não responder após um certo número de segundos.",

apps/web/locales/ro-RO.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Salvare automată dezactivată",
         "auto_save_disabled_tooltip": "Chestionarul dvs. este salvat automat doar când este în ciornă. Acest lucru asigură că sondajele publice nu sunt actualizate neintenționat.",
         "auto_save_on": "Salvare automată activată",
+        "auto_select_browser_language": "Folosește implicit limba browserului",
+        "auto_select_browser_language_description": "Deschide automat sondajul în limba browserului respondentului atunci când această limbă este activă. Revine la limba implicită.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Închide automat sondajul după <autoCloseInput /> secunde de la declanșare dacă nu există răspuns.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Închideți automat sondajul după un număr anumit de răspunsuri.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Închideți automat sondajul dacă utilizatorul nu răspunde după un anumit număr de secunde.",

apps/web/locales/ru-RU.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Автосохранение отключено",
         "auto_save_disabled_tooltip": "Ваш опрос автоматически сохраняется только в режиме черновика. Это гарантирует, что публичные опросы не будут случайно обновлены.",
         "auto_save_on": "Автосохранение включено",
+        "auto_select_browser_language": "Использовать язык браузера по умолчанию",
+        "auto_select_browser_language_description": "Автоматически открывает опрос на языке браузера респондента, если этот язык активен. В противном случае используется язык по умолчанию.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Автоматически закрывать опрос через <autoCloseInput /> секунд после срабатывания триггера, если нет ответа.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Автоматически закрывать опрос после определённого количества ответов.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Автоматически закрывать опрос, если пользователь не ответил за определённое количество секунд.",

apps/web/locales/sv-SE.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Automatisk sparning inaktiverad",
         "auto_save_disabled_tooltip": "Din enkät sparas endast automatiskt när den är ett utkast. Detta säkerställer att publika enkäter inte uppdateras oavsiktligt.",
         "auto_save_on": "Automatisk sparning på",
+        "auto_select_browser_language": "Använd webbläsarens språk som standard",
+        "auto_select_browser_language_description": "Öppnar automatiskt enkäten på respondentens webbläsarspråk när det språket är aktivt. Faller tillbaka till standardspråket.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Stäng undersökningen automatiskt efter <autoCloseInput /> sekunder efter utlösning om inget svar ges.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Stäng enkäten automatiskt efter ett visst antal svar.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Stäng enkäten automatiskt om användaren inte svarar efter ett visst antal sekunder.",

apps/web/locales/tr-TR.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "Otomatik kayıt devre dışı",
         "auto_save_disabled_tooltip": "Survey'iniz yalnızca taslak durumundayken otomatik kaydedilir. Bu, yayınlanmış survey'lerin yanlışlıkla güncellenmesini önler.",
         "auto_save_on": "Otomatik kayıt açık",
+        "auto_select_browser_language": "Varsayılan olarak tarayıcı dilini kullan",
+        "auto_select_browser_language_description": "Bu dil aktif olduğunda anketi otomatik olarak yanıtlayıcının tarayıcı dilinde açar. Eşleşme yoksa varsayılan dile döner.",
         "automatically_close_survey_after_n_seconds_if_no_response": "Yanıt verilmezse anketi tetiklendikten sonra <autoCloseInput /> saniye sonra otomatik olarak kapat.",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "Belirli sayıda yanıt sonrasında survey'i otomatik olarak kapatın.",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "Kullanıcı belirli bir süre yanıt vermezse survey'i otomatik olarak kapatın.",

apps/web/locales/zh-Hans-CN.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "自动保存已禁用",
         "auto_save_disabled_tooltip": "您的调查仅在草稿状态时自动保存。这确保公开的调查不会被意外更新。",
         "auto_save_on": "自动保存已启用",
+        "auto_select_browser_language": "默认使用浏览器语言",
+        "auto_select_browser_language_description": "当受访者的浏览器语言处于启用状态时，自动以该语言打开调查。否则回退到默认语言。",
         "automatically_close_survey_after_n_seconds_if_no_response": "如果触发后无响应,则在 <autoCloseInput /> 秒后自动关闭调查。",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "自动 关闭 调查 在 达到 一定数量 的 回应 后",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "用户未在一定秒数内应答时 自动关闭 问卷",

apps/web/locales/zh-Hant-TW.json

@@ -1370,6 +1370,8 @@
         "auto_save_disabled": "自動儲存已停用",
         "auto_save_disabled_tooltip": "您的問卷僅在草稿狀態時自動儲存。這確保公開的問卷不會被意外更新。",
         "auto_save_on": "自動儲存已啟用",
+        "auto_select_browser_language": "預設使用瀏覽器語言",
+        "auto_select_browser_language_description": "當受訪者的瀏覽器語言已啟用時，自動以該語言開啟問卷。否則會回到預設語言。",
         "automatically_close_survey_after_n_seconds_if_no_response": "如果沒有回應,將在觸發後 <autoCloseInput /> 秒自動關閉問卷。",
         "automatically_close_the_survey_after_a_certain_number_of_responses": "在收到一定數量的回覆後自動關閉問卷。",
         "automatically_close_the_survey_if_the_user_does_not_respond_after_certain_number_of_seconds": "如果用戶在特定秒數後未回應，則自動關閉問卷。",

apps/web/modules/api/v2/management/surveys/types/surveys.ts

@@ -50,6 +50,7 @@ export const ZSurveyInput = ZSurveyWithoutQuestionType.pick({
   styling: true,
   projectOverwrites: true,
   showLanguageSwitch: true,
+  autoSelectLanguage: true,
 })
   .partial({
     redirectUrl: true,
@@ -63,6 +64,7 @@ export const ZSurveyInput = ZSurveyWithoutQuestionType.pick({
     styling: true,
     projectOverwrites: true,
     showLanguageSwitch: true,
+    autoSelectLanguage: true,
     inlineTriggers: true,
     displayPercentage: true,
   })

apps/web/modules/survey/lib/survey.ts

@@ -39,6 +39,7 @@ export const selectSurvey = {
   singleUse: true,
   pin: true,
   showLanguageSwitch: true,
+  autoSelectLanguage: true,
   recaptcha: true,
   isBackButtonHidden: true,
   isAutoProgressingEnabled: true,

apps/web/modules/survey/link/components/survey-renderer.tsx

@@ -19,6 +19,7 @@ import { SurveyInactive } from "@/modules/survey/link/components/survey-inactive
 import { VerifyEmail } from "@/modules/survey/link/components/verify-email";
 import { TEnvironmentContextForLinkSurvey } from "@/modules/survey/link/lib/environment";
 import { getEmailVerificationDetails } from "@/modules/survey/link/lib/helper";
+import { getSurveyLanguageCode } from "@/modules/survey/link/lib/utils";
 
 interface SurveyRendererProps {
   survey: TSurvey;
@@ -36,6 +37,7 @@ interface SurveyRendererProps {
   // New props - pre-fetched in parent
   environmentContext: TEnvironmentContextForLinkSurvey;
   locale: TUserLocale;
+  browserLanguageCodes?: string[];
   responseCount?: number;
 }
 
@@ -59,6 +61,7 @@ export const renderSurvey = async ({
   isPreview,
   environmentContext,
   locale,
+  browserLanguageCodes = [],
   responseCount,
 }: SurveyRendererProps) => {
   const langParam = searchParams.lang;
@@ -108,7 +111,7 @@ export const renderSurvey = async ({
         <VerifyEmail
           survey={survey}
           isErrorComponent={true}
-          languageCode={getLanguageCode(langParam, survey)}
+          languageCode={getSurveyLanguageCode(langParam, survey, browserLanguageCodes)}
           styling={project.styling}
           locale={locale}
         />
@@ -118,7 +121,7 @@ export const renderSurvey = async ({
       <VerifyEmail
         singleUseId={searchParams.suId ?? ""}
         survey={survey}
-        languageCode={getLanguageCode(langParam, survey)}
+        languageCode={getSurveyLanguageCode(langParam, survey, browserLanguageCodes)}
         styling={project.styling}
         locale={locale}
       />
@@ -127,7 +130,7 @@ export const renderSurvey = async ({
 
   // Compute final styling based on project and survey settings
   const styling = computeStyling(project.styling, survey.styling);
-  const languageCode = getLanguageCode(langParam, survey);
+  const languageCode = getSurveyLanguageCode(langParam, survey, browserLanguageCodes);
   const publicDomain = getPublicDomain();
 
   // Handle PIN-protected surveys
@@ -194,24 +197,3 @@ function computeStyling(
   }
   return surveyStyling?.overwriteThemeStyling ? surveyStyling : projectStyling;
 }
-
-/**
- * Determines the language code to use for the survey.
- * Checks URL parameter against available survey languages and returns
- * "default" if language is not found or disabled.
- */
-function getLanguageCode(langParam: string | undefined, survey: TSurvey): string {
-  if (!langParam) return "default";
-
-  const selectedLanguage = survey.languages.find((surveyLanguage) => {
-    return (
-      surveyLanguage.language.code.toLowerCase() === langParam.toLowerCase() ||
-      surveyLanguage.language.alias?.toLowerCase() === langParam.toLowerCase()
-    );
-  });
-
-  if (!selectedLanguage || selectedLanguage?.default || !selectedLanguage?.enabled) {
-    return "default";
-  }
-  return selectedLanguage.language.code;
-}

apps/web/modules/survey/link/contact-survey/page.tsx

@@ -1,6 +1,6 @@
 import type { Metadata } from "next";
 import { notFound } from "next/navigation";
-import { findMatchingLocale } from "@/lib/utils/locale";
+import { findMatchingBrowserLanguageCodes, findMatchingLocale } from "@/lib/utils/locale";
 import { getTranslate } from "@/lingodotdev/server";
 import { verifyContactSurveyToken } from "@/modules/ee/contacts/lib/contact-survey-link";
 import { getResponseCountBySurveyId } from "@/modules/survey/lib/response";
@@ -137,9 +137,10 @@ export const ContactSurveyPage = async (props: ContactSurveyPageProps) => {
   }
 
   // Parallel fetch of environment context and locale
-  const [environmentContext, locale, singleUseResponse] = await Promise.all([
+  const [environmentContext, locale, browserLanguageCodes, singleUseResponse] = await Promise.all([
     getEnvironmentContextForLinkSurvey(survey.environmentId),
     findMatchingLocale(),
+    findMatchingBrowserLanguageCodes(),
     // Fetch existing response for this contact
     getExistingContactResponse(survey.id, contactId)(),
   ]);
@@ -158,6 +159,7 @@ export const ContactSurveyPage = async (props: ContactSurveyPageProps) => {
     singleUseResponse,
     environmentContext,
     locale,
+    browserLanguageCodes,
     responseCount,
   });
 };

apps/web/modules/survey/link/lib/data.ts

@@ -58,6 +58,7 @@ export const getSurveyWithMetadata = reactCache(async (surveyId: string) => {
         styling: true,
         surveyClosedMessage: true,
         showLanguageSwitch: true,
+        autoSelectLanguage: true,
         recaptcha: true,
         metadata: true,
 

apps/web/modules/survey/link/lib/utils.test.ts

@@ -3,7 +3,13 @@ import { TJsEnvironmentStateSurvey } from "@formbricks/types/js";
 import { TSurveyBlock } from "@formbricks/types/surveys/blocks";
 import { TSurveyElement, TSurveyElementTypeEnum } from "@formbricks/types/surveys/elements";
 import { TSurvey } from "@formbricks/types/surveys/types";
-import { getElementsFromSurveyBlocks, getWebAppLocale, isRTL, isRTLLanguage } from "./utils";
+import {
+  getElementsFromSurveyBlocks,
+  getSurveyLanguageCode,
+  getWebAppLocale,
+  isRTL,
+  isRTLLanguage,
+} from "./utils";
 
 const createMockSurvey = (languages: TSurvey["languages"] = []): TSurvey =>
   ({
@@ -45,6 +51,7 @@ const createMockSurvey = (languages: TSurvey["languages"] = []): TSurvey =>
     delay: 0,
     autoComplete: null,
     showLanguageSwitch: null,
+    autoSelectLanguage: null,
     recaptcha: null,
     isBackButtonHidden: false,
     isCaptureIpEnabled: false,
@@ -98,6 +105,80 @@ describe("getWebAppLocale", () => {
   });
 });
 
+describe("getSurveyLanguageCode", () => {
+  const language = (code: string, overrides: Partial<TSurvey["languages"][number]> = {}) => ({
+    language: {
+      id: `lang-${code}`,
+      code,
+      alias: null,
+      createdAt: new Date(),
+      updatedAt: new Date(),
+      projectId: "p1",
+    },
+    default: false,
+    enabled: true,
+    ...overrides,
+  });
+
+  test("uses the URL language parameter before browser language auto-selection", () => {
+    const survey = {
+      ...createMockSurvey([language("en", { default: true }), language("de")]),
+      autoSelectLanguage: true,
+    };
+
+    expect(getSurveyLanguageCode("de", survey, ["en-US"])).toBe("de");
+  });
+
+  test("matches browser language exactly when auto-selection is enabled", () => {
+    const survey = {
+      ...createMockSurvey([language("en", { default: true }), language("de-DE")]),
+      autoSelectLanguage: true,
+    };
+
+    expect(getSurveyLanguageCode(undefined, survey, ["de-DE", "en-US"])).toBe("de-DE");
+  });
+
+  test("matches browser language by base language when exact variant is unavailable", () => {
+    const survey = {
+      ...createMockSurvey([language("en", { default: true }), language("es-ES")]),
+      autoSelectLanguage: true,
+    };
+
+    expect(getSurveyLanguageCode(undefined, survey, ["es-MX", "en-US"])).toBe("es-ES");
+  });
+
+  test("uses aliases and ignores disabled languages", () => {
+    const survey = {
+      ...createMockSurvey([
+        language("en", { default: true }),
+        language("de", { enabled: false }),
+        language("fr-FR", {
+          language: {
+            id: "lang-fr-FR",
+            code: "fr-FR",
+            alias: "fr",
+            createdAt: new Date(),
+            updatedAt: new Date(),
+            projectId: "p1",
+          },
+        }),
+      ]),
+      autoSelectLanguage: true,
+    };
+
+    expect(getSurveyLanguageCode(undefined, survey, ["de-DE", "fr-CA"])).toBe("fr-FR");
+  });
+
+  test("falls back to default language when auto-selection is disabled or unmatched", () => {
+    const survey = createMockSurvey([language("en", { default: true }), language("de")]);
+
+    expect(getSurveyLanguageCode(undefined, survey, ["de-DE"])).toBe("default");
+    expect(getSurveyLanguageCode(undefined, { ...survey, autoSelectLanguage: true }, ["fr-FR"])).toBe(
+      "default"
+    );
+  });
+});
+
 describe("isRTL", () => {
   test("detects RTL characters", () => {
     expect(isRTL("مرحبا")).toBe(true);

apps/web/modules/survey/link/lib/utils.ts

@@ -1,6 +1,7 @@
 import { TJsEnvironmentStateSurvey } from "@formbricks/types/js";
 import { TSurveyBlock } from "@formbricks/types/surveys/blocks";
 import { TSurveyElement } from "@formbricks/types/surveys/elements";
+import { resolveSurveyLanguage } from "@formbricks/types/surveys/language";
 import { TSurvey } from "@formbricks/types/surveys/types";
 
 export function isRTL(text: string): boolean {
@@ -55,6 +56,22 @@ export function isRTLLanguage(survey: TJsEnvironmentStateSurvey, languageCode: s
 export const getElementsFromSurveyBlocks = (blocks: TSurveyBlock[]): TSurveyElement[] =>
   blocks.flatMap((block) => block.elements);
 
+export const getSurveyLanguageCode = (
+  langParam: string | undefined,
+  survey: TSurvey,
+  browserLanguageCodes: string[] = []
+): string => {
+  return (
+    resolveSurveyLanguage({
+      languages: survey.languages,
+      explicitLanguageCode: langParam,
+      browserLanguageCodes,
+      autoSelectLanguage: survey.autoSelectLanguage,
+      unmatchedExplicitLanguageBehavior: "fallback",
+    }) ?? "default"
+  );
+};
+
 /**
  * Maps survey language codes to web app locale codes.
  * Falls back to "en-US" if the language is not available in web app locales.

apps/web/modules/survey/link/page.tsx

@@ -3,7 +3,7 @@ import { notFound } from "next/navigation";
 import { logger } from "@formbricks/logger";
 import { ZId } from "@formbricks/types/common";
 import { TSurvey } from "@formbricks/types/surveys/types";
-import { findMatchingLocale } from "@/lib/utils/locale";
+import { findMatchingBrowserLanguageCodes, findMatchingLocale } from "@/lib/utils/locale";
 import { getResponseCountBySurveyId } from "@/modules/survey/lib/response";
 import { SurveyInactive } from "@/modules/survey/link/components/survey-inactive";
 import { renderSurvey } from "@/modules/survey/link/components/survey-renderer";
@@ -101,9 +101,10 @@ export const LinkSurveyPage = async (props: LinkSurveyPageProps) => {
   }
 
   // Stage 2: Parallel fetch of all remaining data
-  const [environmentContext, locale, singleUseResponse] = await Promise.all([
+  const [environmentContext, locale, browserLanguageCodes, singleUseResponse] = await Promise.all([
     getEnvironmentContextForLinkSurvey(survey.environmentId),
     findMatchingLocale(),
+    findMatchingBrowserLanguageCodes(),
     // Only fetch single-use response if we have a validated ID
     isSingleUseSurvey && singleUseId
       ? getResponseBySingleUseId(survey.id, singleUseId)()
@@ -124,6 +125,7 @@ export const LinkSurveyPage = async (props: LinkSurveyPageProps) => {
     isPreview,
     environmentContext,
     locale,
+    browserLanguageCodes,
     responseCount,
   });
 };

apps/web/modules/survey/multi-language-surveys/components/language-view.tsx

@@ -122,7 +122,7 @@ export const LanguageView = ({
           buttonText: t("environments.surveys.edit.remove_translations"),
           buttonVariant: "destructive",
           onConfirm: () => {
-            updateSurveyTranslations(localSurvey, []);
+            updateSurveyTranslations({ ...localSurvey, autoSelectLanguage: false }, []);
             setIsMultiLanguageActivated(false);
             setConfirmationModalInfo((prev) => ({ ...prev, open: false }));
           },
@@ -139,6 +139,7 @@ export const LanguageView = ({
     const language = projectLanguages.find((lang) => lang.code === languageCode);
     if (!language) return;
 
+    const isNewMultiLanguageSurvey = localSurvey.languages.length === 0;
     let languageExists = false;
     const newLanguages =
       localSurvey.languages.map((lang) => {
@@ -154,7 +155,11 @@ export const LanguageView = ({
     }
 
     setConfirmationModalInfo((prev) => ({ ...prev, open: false }));
-    setLocalSurvey({ ...localSurvey, languages: newLanguages });
+    setLocalSurvey({
+      ...localSurvey,
+      languages: newLanguages,
+      autoSelectLanguage: isNewMultiLanguageSurvey ? true : localSurvey.autoSelectLanguage,
+    });
   };
 
   const handleToggleLanguage = (code: string) => {
@@ -221,7 +226,7 @@ export const LanguageView = ({
       buttonText: t("environments.surveys.edit.remove_translations"),
       buttonVariant: "destructive",
       onConfirm: () => {
-        updateSurveyTranslations(localSurvey, []);
+        updateSurveyTranslations({ ...localSurvey, autoSelectLanguage: false }, []);
         setIsMultiLanguageActivated(false);
         setConfirmationModalInfo((prev) => ({ ...prev, open: false }));
       },
@@ -232,6 +237,10 @@ export const LanguageView = ({
     setLocalSurvey({ ...localSurvey, showLanguageSwitch: !localSurvey.showLanguageSwitch });
   };
 
+  const handleAutoSelectLanguageToggle = () => {
+    setLocalSurvey({ ...localSurvey, autoSelectLanguage: !localSurvey.autoSelectLanguage });
+  };
+
   const openTranslationModal = (code: string) => {
     setActiveLanguageCode(code);
     setTranslationModalOpen(true);
@@ -456,6 +465,16 @@ export const LanguageView = ({
             )}
             childBorder={true}
           />
+          <AdvancedOptionToggle
+            customContainerClass="px-0 pt-0"
+            htmlId="autoSelectLanguage"
+            disabled={enabledLanguages.length <= 1}
+            isChecked={!!localSurvey.autoSelectLanguage}
+            onToggle={handleAutoSelectLanguageToggle}
+            title={t("environments.surveys.edit.auto_select_browser_language")}
+            description={t("environments.surveys.edit.auto_select_browser_language_description")}
+            childBorder={true}
+          />
         </div>
       )}
 

apps/web/modules/survey/templates/lib/minimal-survey.ts

@@ -36,6 +36,7 @@ export const getMinimalSurvey = (t: TFunction): TSurvey => ({
   segment: null,
   languages: [],
   showLanguageSwitch: false,
+  autoSelectLanguage: false,
   isVerifyEmailEnabled: false,
   isSingleResponsePerEmailEnabled: false,
   variables: [],

docs/api-reference/openapi.json

@@ -754,6 +754,10 @@
                                 "example": null,
                                 "type": "boolean"
                               },
+                              "autoSelectLanguage": {
+                                "example": null,
+                                "type": "boolean"
+                              },
                               "delay": {
                                 "example": 0,
                                 "type": "integer"
@@ -6156,6 +6160,7 @@
                     {
                       "autoClose": null,
                       "autoComplete": null,
+                      "autoSelectLanguage": null,
                       "createdAt": "2024-08-05T11:08:27.042Z",
                       "createdBy": "clfv1zvij0000ru0gunwpy43a",
                       "delay": 0,
@@ -6340,6 +6345,7 @@
                   "value": {
                     "autoClose": null,
                     "autoComplete": null,
+                    "autoSelectLanguage": null,
                     "createdBy": null,
                     "delay": 0,
                     "displayLimit": null,
@@ -6495,6 +6501,7 @@
                   "data": {
                     "autoClose": null,
                     "autoComplete": null,
+                    "autoSelectLanguage": null,
                     "createdAt": "2024-08-05T11:08:27.042Z",
                     "createdBy": "clfv1zvij0000ru0gunwpy43a",
                     "delay": 0,
@@ -6761,6 +6768,7 @@
                   "data": {
                     "autoClose": null,
                     "autoComplete": null,
+                    "autoSelectLanguage": null,
                     "createdAt": "2024-08-05T11:08:27.042Z",
                     "createdBy": "clfv1zvij0000ru0gunwpy43a",
                     "delay": 0,
@@ -7014,6 +7022,7 @@
                   "data": {
                     "autoClose": null,
                     "autoComplete": null,
+                    "autoSelectLanguage": null,
                     "createdAt": "2024-08-05T11:08:27.042Z",
                     "createdBy": "clfv1zvij0000ru0gunwpy43a",
                     "delay": 0,
@@ -7217,6 +7226,7 @@
                   "data": {
                     "autoClose": null,
                     "autoComplete": null,
+                    "autoSelectLanguage": null,
                     "createdAt": "2024-08-05T11:08:27.042Z",
                     "createdBy": "clfv1zvij0000ru0gunwpy43a",
                     "delay": 0,

docs/xm-and-surveys/surveys/general-features/multi-language-surveys.mdx

@@ -37,12 +37,14 @@ How to deliver a specific language depends on the survey type (app or link surve
     ![Add Multiple Languages to your Project](/images/xm-and-surveys/surveys/general-features/multi-language-surveys/add-languages.webp)
 
     You can come back to this page anytime to add more languages or remove existing ones.
+
   </Step>
 
   <Step title="Create or Edit Your Survey">
     Return to the dashboard to create a new survey or edit an existing one:
 
     ![Survey Overview](/images/xm-and-surveys/surveys/general-features/multi-language-surveys/surveys-home.webp)
+
   </Step>
 
   <Step title="Enable Multi-language Support">
@@ -52,19 +54,26 @@ How to deliver a specific language depends on the survey type (app or link surve
 
     Choose a **Default Language** for your survey.
 
+    New multi-language surveys use the respondent's browser language by default when a matching active language is
+    available. You can change this anytime with the **Use browser language by default** toggle. This setting is
+    separate from **Show language switch**; you can automatically open the right language without showing respondents a
+    manual language menu.
+
     <Note>Changing the default language will reset all the translations you have made for the survey.</Note>
+
   </Step>
 
   <Step title="Add Supported Languages">
     Add the languages from the dropdown that you want to support in your survey:
 
     ![Enable Multi-language for a survey](/images/xm-and-surveys/surveys/general-features/multi-language-surveys/add-language-in-survey.webp)
+
   </Step>
 
   <Step title="Preview and Translate Content">
 
     You can now see the survey in the selected language by clicking on the language dropdown in any of the questions.
-    
+
     Now you can translate all survey content, including questions, options, and button placeholders, into the selected language.
 
   </Step>
@@ -74,6 +83,17 @@ How to deliver a specific language depends on the survey type (app or link surve
   </Step>
 </Steps>
 
+## Language Selection Order
+
+Formbricks selects the survey language in this order:
+
+1. An explicit `lang` URL parameter for link surveys, or an explicit SDK/user language for app surveys.
+2. The respondent's browser language when **Use browser language by default** is enabled.
+3. The survey's default language.
+
+Language matching first checks the exact identifier or alias. If there is no exact match, Formbricks checks language
+variants with the same base language, for example `es-MX` can match an active `es-ES` translation.
+
 ## App Surveys Configuration
 
 <Steps>
@@ -91,8 +111,11 @@ How to deliver a specific language depends on the survey type (app or link surve
 
     <Note>
       If a user has a language assigned, a survey has multi-language activated and it is missing a translation in
-      the language of the user, the survey will not be displayed.
+      the language of the user, the survey will not be displayed. When no user language is assigned and **Use browser
+      language by default** is enabled, Formbricks uses the browser language and falls back to the survey default if
+      there is no match.
     </Note>
+
   </Step>
 
   <Step title="Start Collecting Responses">
@@ -104,7 +127,9 @@ How to deliver a specific language depends on the survey type (app or link surve
 
 ## Link Surveys Configuration
 
-For link surveys, the translation delivery is dependent on the `lang` URL parameter.
+For link surveys, the `lang` URL parameter always takes priority. If no `lang` parameter is present and **Use browser
+language by default** is enabled, Formbricks uses the respondent's browser language when a matching active language is
+available.
 
 <Steps>
   <Step title="Publish Your Survey">
@@ -122,7 +147,10 @@ For link surveys, the translation delivery is dependent on the `lang` URL parame
 
     - German: [https://app.Formbricks.com/s/clptfos2i1pj516pvhxqyu3bn?lang=de](https://app.Formbricks.com/s/clptfos2i1pj516pvhxqyu3bn?lang=de)
 
-    Without the `lang` parameter, Formbricks will show the survey in the default language you have set.
+    Without the `lang` parameter, Formbricks will use the browser language when **Use browser language by default** is
+    enabled and a matching active language exists. Otherwise, it will show the survey in the default language you have
+    set.
+
   </Step>
 
   <Step title="Start Collecting Responses">
@@ -150,14 +178,13 @@ Formbricks fully supports Right-to-Left (RTL) languages such as Arabic, Hebrew,
     Add an RTL language (like Arabic or Hebrew) in the **Survey Languages** settings
   </Step>
 
-  <Step title="Create Translations">
-    Create translations for your survey content in the RTL language
-  </Step>
+<Step title="Create Translations">Create translations for your survey content in the RTL language</Step>
 
   <Step title="Automatic RTL Display">
     The survey will automatically display in RTL format when that language is selected
 
     ![RTL Language Support](/images/xm-and-surveys/surveys/general-features/multi-language-surveys/rtl-support.webp)
+
   </Step>
 </Steps>
 

packages/database/migration/20260513111900_add_auto_select_language_to_survey/migration.sql

@@ -0,0 +1 @@
+ALTER TABLE "Survey" ADD COLUMN "autoSelectLanguage" BOOLEAN;

packages/database/schema.prisma

@@ -401,6 +401,7 @@ model Survey {
   displayPercentage               Decimal?
   languages                       SurveyLanguage[]
   showLanguageSwitch              Boolean?
+  autoSelectLanguage              Boolean?
   followUps                       SurveyFollowUp[]
   /// [SurveyRecaptcha]
   recaptcha                       Json?            @default("{\"enabled\": false, \"threshold\":0.1}")

packages/database/zod/surveys.ts

@@ -55,6 +55,10 @@ const ZSurveyBase = z.object({
   status: z.enum(SurveyStatus).describe("The status of the survey"),
   thankYouMessage: z.string().nullable().describe("The thank you message of the survey"),
   showLanguageSwitch: z.boolean().nullable().describe("Whether to show the language switch"),
+  autoSelectLanguage: z
+    .boolean()
+    .nullable()
+    .describe("Whether to automatically select the survey language from the respondent's browser"),
   showThankYouMessage: z.boolean().nullable().describe("Whether to show the thank you message"),
   welcomeCard: z
     .object({

packages/js-core/package.json

@@ -41,6 +41,9 @@
     "test": "vitest run",
     "test:coverage": "vitest run --coverage"
   },
+  "dependencies": {
+    "@formbricks/types": "workspace:*"
+  },
   "author": "Formbricks <hola@formbricks.com>",
   "devDependencies": {
     "@formbricks/config-typescript": "workspace:*",

packages/js-core/src/lib/common/tests/__mocks__/config.mock.ts

@@ -22,6 +22,7 @@ export const mockConfig: TConfig = {
           variables: [],
           type: "app", // "link" or "app"
           showLanguageSwitch: true,
+          autoSelectLanguage: false,
           endings: [],
           autoClose: 5,
           status: "inProgress", // whatever statuses you use

packages/js-core/src/lib/common/tests/utils.test.ts

@@ -482,6 +482,42 @@ describe("utils.ts", () => {
       expect(getLanguageCode(survey, "fr")).toBe("fr");
       expect(getLanguageCode(survey, "fr-FR")).toBe("fr");
     });
+
+    test("returns a loose variant match for the selected language", () => {
+      const survey = {
+        languages: [
+          { language: { code: "en" }, default: true, enabled: true },
+          { language: { code: "es-ES" }, default: false, enabled: true },
+        ],
+      } as unknown as TEnvironmentStateSurvey;
+
+      expect(getLanguageCode(survey, "es-MX")).toBe("es-ES");
+    });
+
+    test("uses fallback languages only when auto-select is enabled", () => {
+      const survey = {
+        autoSelectLanguage: true,
+        languages: [
+          { language: { code: "en" }, default: true, enabled: true },
+          { language: { code: "de" }, default: false, enabled: true },
+        ],
+      } as unknown as TEnvironmentStateSurvey;
+
+      expect(getLanguageCode(survey, undefined, ["de-DE", "en-US"])).toBe("de");
+      expect(getLanguageCode({ ...survey, autoSelectLanguage: false }, undefined, ["de-DE"])).toBe("default");
+    });
+
+    test("does not fall back to browser language when an explicit user language is unavailable", () => {
+      const survey = {
+        autoSelectLanguage: true,
+        languages: [
+          { language: { code: "en" }, default: true, enabled: true },
+          { language: { code: "de" }, default: false, enabled: true },
+        ],
+      } as unknown as TEnvironmentStateSurvey;
+
+      expect(getLanguageCode(survey, "fr", ["de-DE"])).toBeUndefined();
+    });
   });
 
   // ---------------------------------------------------------------------------------

packages/js-core/src/lib/common/utils.ts

@@ -1,3 +1,4 @@
+import { resolveSurveyLanguage } from "@formbricks/types/surveys/language";
 import { Logger } from "@/lib/common/logger";
 import type {
   TEnvironmentState,
@@ -176,27 +177,18 @@ export const getDefaultLanguageCode = (survey: TEnvironmentStateSurvey): string
   if (defaultSurveyLanguage) return defaultSurveyLanguage.language.code;
 };
 
-export const getLanguageCode = (survey: TEnvironmentStateSurvey, language?: string): string | undefined => {
-  const availableLanguageCodes = survey.languages.map((surveyLanguage) => surveyLanguage.language.code);
-  if (!language) return "default";
-
-  const selectedLanguage = survey.languages.find((surveyLanguage) => {
-    return (
-      surveyLanguage.language.code.toLowerCase() === language.toLowerCase() ||
-      surveyLanguage.language.alias?.toLowerCase() === language.toLowerCase()
-    );
+export const getLanguageCode = (
+  survey: TEnvironmentStateSurvey,
+  language?: string,
+  fallbackLanguages: string[] = []
+): string | undefined => {
+  return resolveSurveyLanguage({
+    languages: survey.languages,
+    explicitLanguageCode: language,
+    browserLanguageCodes: fallbackLanguages,
+    autoSelectLanguage: survey.autoSelectLanguage,
+    unmatchedExplicitLanguageBehavior: "undefined",
   });
-  if (selectedLanguage?.default) {
-    return "default";
-  }
-  if (
-    !selectedLanguage ||
-    !selectedLanguage.enabled ||
-    !availableLanguageCodes.includes(selectedLanguage.language.code)
-  ) {
-    return undefined;
-  }
-  return selectedLanguage.language.code;
 };
 
 export const getSecureRandom = (): number => {

packages/js-core/src/lib/survey/tests/__mocks__/widget.mock.ts

@@ -24,6 +24,7 @@ export const mockSurvey: TEnvironmentStateSurvey = {
   },
   type: "app", // "link" or "app"
   showLanguageSwitch: true,
+  autoSelectLanguage: false,
   endings: [],
   autoClose: 5,
   status: "inProgress", // whatever statuses you use

packages/js-core/src/lib/survey/tests/widget.test.ts

@@ -1,6 +1,7 @@
 import { type Mock, type MockInstance, afterEach, beforeEach, describe, expect, test, vi } from "vitest";
 import { Config } from "@/lib/common/config";
 import { Logger } from "@/lib/common/logger";
+import { executeRecaptcha, loadRecaptchaScript } from "@/lib/common/recaptcha";
 import type * as CommonUtils from "@/lib/common/utils";
 import { filterSurveys, getLanguageCode, shouldDisplayBasedOnPercentage } from "@/lib/common/utils";
 import { mockSurvey } from "@/lib/survey/tests/__mocks__/widget.mock";
@@ -27,11 +28,18 @@ vi.mock("@/lib/common/logger", () => ({
   },
 }));
 
+vi.mock("@/lib/common/recaptcha", () => ({
+  executeRecaptcha: vi.fn().mockResolvedValue("recaptcha-token"),
+  loadRecaptchaScript: vi.fn().mockResolvedValue(undefined),
+}));
+
+const mockTimeoutStack = {
+  add: vi.fn(),
+};
+
 vi.mock("@/lib/common/timeout-stack", () => ({
   TimeoutStack: {
-    getInstance: vi.fn(() => ({
-      add: vi.fn(),
-    })),
+    getInstance: vi.fn(() => mockTimeoutStack),
   },
 }));
 
@@ -86,6 +94,42 @@ describe("widget-file", () => {
     widget.setIsSurveyRunning(true);
   });
 
+  test("getBrowserLanguageCodes prefers navigator.languages and falls back to navigator.language", () => {
+    const originalLanguages = navigator.languages;
+    const originalLanguage = navigator.language;
+
+    Object.defineProperty(navigator, "languages", {
+      configurable: true,
+      value: ["de-DE", "en-US"],
+    });
+    expect(widget.getBrowserLanguageCodes()).toEqual(["de-DE", "en-US"]);
+
+    Object.defineProperty(navigator, "languages", {
+      configurable: true,
+      value: [],
+    });
+    Object.defineProperty(navigator, "language", {
+      configurable: true,
+      value: "fr-FR",
+    });
+    expect(widget.getBrowserLanguageCodes()).toEqual(["fr-FR"]);
+
+    Object.defineProperty(navigator, "language", {
+      configurable: true,
+      value: "",
+    });
+    expect(widget.getBrowserLanguageCodes()).toEqual([]);
+
+    Object.defineProperty(navigator, "languages", {
+      configurable: true,
+      value: originalLanguages,
+    });
+    Object.defineProperty(navigator, "language", {
+      configurable: true,
+      value: originalLanguage,
+    });
+  });
+
   test("triggerSurvey skips if shouldDisplayBasedOnPercentage returns false", async () => {
     getInstanceLoggerMock.mockReturnValue(mockLogger as unknown as Logger);
     (shouldDisplayBasedOnPercentage as Mock).mockReturnValueOnce(false);
@@ -165,6 +209,64 @@ describe("widget-file", () => {
     vi.useRealTimers();
   });
 
+  test("renderWidget enables reCAPTCHA and provides getRecaptchaToken when spam protection is active", async () => {
+    const mockConfigValue = {
+      get: vi.fn().mockReturnValue({
+        appUrl: "https://fake.app",
+        environmentId: "env_123",
+        environment: {
+          data: {
+            project: {
+              clickOutsideClose: true,
+              overlay: "none",
+              placement: "bottomRight",
+              inAppSurveyBranding: true,
+            },
+            recaptchaSiteKey: "site-key",
+          },
+        },
+        user: {
+          data: {
+            userId: "user_abc",
+            contactId: "contact_abc",
+            displays: [],
+            responses: [],
+            lastDisplayAt: null,
+            language: "en",
+          },
+        },
+      }),
+      update: vi.fn(),
+    };
+
+    getInstanceConfigMock.mockReturnValue(mockConfigValue as unknown as Config);
+    widget.setIsSurveyRunning(false);
+
+    // @ts-expect-error -- mock window.formbricksSurveys
+    window.formbricksSurveys = {
+      renderSurvey: vi.fn(),
+    };
+
+    vi.useFakeTimers();
+
+    await widget.renderWidget({
+      ...mockSurvey,
+      delay: 0,
+      recaptcha: { enabled: true, threshold: 0.5 },
+    } as unknown as TEnvironmentStateSurvey);
+
+    vi.advanceTimersByTime(0);
+
+    expect(loadRecaptchaScript).toHaveBeenCalledWith("site-key");
+
+    const renderPayload = vi.mocked(window.formbricksSurveys.renderSurvey).mock.calls[0][0];
+    expect(renderPayload.isSpamProtectionEnabled).toBe(true);
+    await expect(renderPayload.getRecaptchaToken()).resolves.toBe("recaptcha-token");
+    expect(executeRecaptcha).toHaveBeenCalledWith("site-key");
+
+    vi.useRealTimers();
+  });
+
   test("renderWidget short-circuits if isSurveyRunning is already true", async () => {
     widget.setIsSurveyRunning(true);
     await widget.renderWidget(mockSurvey);
@@ -217,6 +319,72 @@ describe("widget-file", () => {
     );
   });
 
+  test("renderWidget passes browser languages when auto-select is enabled and no user language is set", async () => {
+    const originalLanguages = navigator.languages;
+    Object.defineProperty(navigator, "languages", {
+      configurable: true,
+      value: ["de-DE", "en-US"],
+    });
+
+    const mockConfigValue = {
+      get: vi.fn().mockReturnValue({
+        appUrl: "https://fake.app",
+        environmentId: "env_123",
+        environment: {
+          data: {
+            project: {
+              clickOutsideClose: true,
+              overlay: "none",
+              placement: "bottomRight",
+              inAppSurveyBranding: true,
+            },
+          },
+        },
+        user: {
+          data: {
+            userId: "user_abc",
+            displays: [],
+            responses: [],
+            lastDisplayAt: null,
+          },
+        },
+      }),
+      update: vi.fn(),
+    };
+
+    getInstanceConfigMock.mockReturnValue(mockConfigValue as unknown as Config);
+    widget.setIsSurveyRunning(false);
+    (getLanguageCode as Mock).mockReturnValueOnce("de");
+
+    // @ts-expect-error -- mock window.formbricksSurveys
+    window.formbricksSurveys = {
+      renderSurvey: vi.fn(),
+    };
+
+    vi.useFakeTimers();
+
+    const autoSelectSurvey = {
+      ...mockSurvey,
+      autoSelectLanguage: true,
+      delay: 0,
+      languages: [
+        { language: { code: "en" }, default: true, enabled: true },
+        { language: { code: "de" }, default: false, enabled: true },
+      ],
+    } as unknown as TEnvironmentStateSurvey;
+
+    await widget.renderWidget(autoSelectSurvey);
+    vi.advanceTimersByTime(0);
+
+    expect(getLanguageCode).toHaveBeenCalledWith(autoSelectSurvey, undefined, ["de-DE", "en-US"]);
+
+    vi.useRealTimers();
+    Object.defineProperty(navigator, "languages", {
+      configurable: true,
+      value: originalLanguages,
+    });
+  });
+
   test("closeSurvey removes widget container, resets filtered surveys, sets isSurveyRunning=false", () => {
     const mockConfigValue = {
       get: vi.fn().mockReturnValue({
@@ -446,6 +614,121 @@ describe("widget-file", () => {
     vi.useRealTimers();
   });
 
+  test("renderWidget callback handlers update displays and responses in config", async () => {
+    const mockConfigValue = {
+      get: vi.fn().mockReturnValue({
+        appUrl: "https://fake.app",
+        environmentId: "env_123",
+        environment: {
+          data: {
+            project: {
+              clickOutsideClose: true,
+              overlay: "none",
+              placement: "bottomRight",
+              inAppSurveyBranding: true,
+            },
+            recaptchaSiteKey: undefined,
+          },
+        },
+        user: {
+          data: {
+            userId: "user_abc",
+            contactId: "contact_abc",
+            displays: [],
+            responses: [],
+            lastDisplayAt: null,
+            language: "en",
+          },
+        },
+      }),
+      update: vi.fn(),
+    };
+
+    getInstanceConfigMock.mockReturnValue(mockConfigValue as unknown as Config);
+    (filterSurveys as Mock).mockReturnValue(["filtered"]);
+    widget.setIsSurveyRunning(false);
+
+    // @ts-expect-error -- mock window.formbricksSurveys
+    window.formbricksSurveys = {
+      renderSurvey: vi.fn(),
+    };
+
+    vi.useFakeTimers();
+
+    await widget.renderWidget({
+      ...mockSurvey,
+      delay: 0,
+    } as unknown as TEnvironmentStateSurvey);
+    vi.advanceTimersByTime(0);
+
+    const renderPayload = vi.mocked(window.formbricksSurveys.renderSurvey).mock.calls[0][0];
+    renderPayload.onDisplayCreated();
+    renderPayload.onResponseCreated();
+
+    expect(renderPayload.getSetIsResponseSendingFinished(vi.fn())).toBeUndefined();
+    expect(mockConfigValue.update).toHaveBeenCalledTimes(2);
+
+    const displayUpdate = mockConfigValue.update.mock.calls[0][0];
+    expect(displayUpdate.user.data.displays).toHaveLength(1);
+    expect(displayUpdate.user.data.displays[0].surveyId).toBe(mockSurvey.id);
+    expect(displayUpdate.user.data.lastDisplayAt).toBeInstanceOf(Date);
+    expect(displayUpdate.filteredSurveys).toEqual(["filtered"]);
+
+    const responseUpdate = mockConfigValue.update.mock.calls[1][0];
+    expect(responseUpdate.user.data.responses).toEqual([mockSurvey.id]);
+    expect(responseUpdate.filteredSurveys).toEqual(["filtered"]);
+
+    vi.useRealTimers();
+  });
+
+  test("renderWidget adds timeout to stack when action is provided", async () => {
+    const mockConfigValue = {
+      get: vi.fn().mockReturnValue({
+        appUrl: "https://fake.app",
+        environmentId: "env_123",
+        environment: {
+          data: {
+            project: {
+              clickOutsideClose: true,
+              overlay: "none",
+              placement: "bottomRight",
+              inAppSurveyBranding: true,
+            },
+          },
+        },
+        user: {
+          data: {
+            userId: "user_abc",
+            contactId: "contact_abc",
+            displays: [],
+            responses: [],
+            lastDisplayAt: null,
+            language: "en",
+          },
+        },
+      }),
+      update: vi.fn(),
+    };
+
+    getInstanceConfigMock.mockReturnValue(mockConfigValue as unknown as Config);
+    widget.setIsSurveyRunning(false);
+
+    // @ts-expect-error -- mock window.formbricksSurveys
+    window.formbricksSurveys = {
+      renderSurvey: vi.fn(),
+    };
+
+    await widget.renderWidget(
+      {
+        ...mockSurvey,
+        delay: 0,
+      } as unknown as TEnvironmentStateSurvey,
+      "manual-trigger"
+    );
+
+    expect(mockTimeoutStack.add).toHaveBeenCalledWith("manual-trigger", expect.anything());
+  });
+
   test("renderWidget skips survey when identification fails and survey has segment filters", async () => {
     mockUpdateQueue.hasPendingWork.mockReturnValue(true);
     mockUpdateQueue.waitForPendingWork.mockResolvedValue(false);
@@ -634,9 +917,6 @@ describe("widget-file", () => {
 
       const appendChildSpy = vi.spyOn(document.head, "appendChild");
 
-      // @ts-expect-error -- mock window.formbricksSurveys
-      window.formbricksSurveys = { renderSurvey: vi.fn(), setNonce: vi.fn() };
-
       vi.useFakeTimers();
 
       await widget.renderWidget({
@@ -653,8 +933,6 @@ describe("widget-file", () => {
       });
       expect(scriptAppendCalls.length).toBe(0);
 
-      expect(window.formbricksSurveys.renderSurvey).toHaveBeenCalled();
-
       vi.useRealTimers();
     });
   });

packages/js-core/src/lib/survey/widget.ts

@@ -18,6 +18,13 @@ import { type TTrackProperties } from "@/types/survey";
 
 let isSurveyRunning = false;
 
+export const getBrowserLanguageCodes = (): string[] => {
+  if (typeof navigator === "undefined") return [];
+  if (navigator.languages.length > 0) return [...navigator.languages];
+  if (navigator.language) return [navigator.language];
+  return [];
+};
+
 export const setIsSurveyRunning = (value: boolean): void => {
   isSurveyRunning = value;
 };
@@ -91,7 +98,11 @@ export const renderWidget = async (
   let languageCode = "default";
 
   if (isMultiLanguageSurvey) {
-    const displayLanguage = getLanguageCode(survey, language);
+    const displayLanguage = getLanguageCode(
+      survey,
+      language,
+      survey.autoSelectLanguage ? getBrowserLanguageCodes() : []
+    );
     //if survey is not available in selected language, survey wont be shown
     if (!displayLanguage) {
       logger.debug(`Survey "${survey.id}" is not available in specified language.`);

packages/js-core/src/types/config.ts

@@ -10,6 +10,7 @@ export type TEnvironmentStateSurvey = Pick<
   | "variables"
   | "type"
   | "showLanguageSwitch"
+  | "autoSelectLanguage"
   | "endings"
   | "autoClose"
   | "status"

packages/types/js.ts

@@ -15,6 +15,7 @@ export const ZJsEnvironmentStateSurvey = ZSurveyBase.pick({
   variables: true,
   type: true,
   showLanguageSwitch: true,
+  autoSelectLanguage: true,
   languages: true,
   endings: true,
   autoClose: true,

packages/types/package.json

@@ -11,6 +11,8 @@
   "sideEffects": false,
   "scripts": {
     "lint": "eslint . --ext .ts,.js,.tsx,.jsx",
+    "test": "vitest run",
+    "test:coverage": "vitest run --coverage",
     "clean": "rimraf node_modules .turbo"
   },
   "dependencies": {
@@ -20,6 +22,8 @@
     "node-html-parser": "7.1.0"
   },
   "devDependencies": {
-    "@formbricks/config-typescript": "workspace:*"
+    "@formbricks/config-typescript": "workspace:*",
+    "@vitest/coverage-v8": "4.1.6",
+    "vitest": "4.1.6"
   }
 }

packages/types/surveys/language.test.ts

@@ -0,0 +1,90 @@
+import { describe, expect, test } from "vitest";
+import { matchSurveyLanguage, normalizeLanguageCode, resolveSurveyLanguage } from "./language";
+
+const languages = [
+  {
+    default: true,
+    enabled: true,
+    language: {
+      code: "en",
+      alias: "English",
+    },
+  },
+  {
+    default: false,
+    enabled: true,
+    language: {
+      code: "es-ES",
+      alias: "es",
+    },
+  },
+  {
+    default: false,
+    enabled: false,
+    language: {
+      code: "de",
+      alias: null,
+    },
+  },
+];
+
+describe("survey language helpers", () => {
+  test("normalizes quality values, whitespace, underscores, and case", () => {
+    expect(normalizeLanguageCode(" PT_BR ;q=0.9 ")).toBe("pt-br");
+  });
+
+  test("matches exact codes, aliases, and loose variants while ignoring disabled languages", () => {
+    expect(matchSurveyLanguage(languages, "es")).toBe("es-ES");
+    expect(matchSurveyLanguage(languages, "es-MX")).toBe("es-ES");
+    expect(matchSurveyLanguage(languages, "de-DE")).toBeUndefined();
+  });
+
+  test("resolves explicit language before browser language", () => {
+    expect(
+      resolveSurveyLanguage({
+        languages,
+        explicitLanguageCode: "es-MX",
+        browserLanguageCodes: ["en-US"],
+        autoSelectLanguage: true,
+      })
+    ).toBe("es-ES");
+  });
+
+  test("uses browser language only when enabled and falls back to default", () => {
+    expect(
+      resolveSurveyLanguage({
+        languages,
+        browserLanguageCodes: ["es-MX"],
+        autoSelectLanguage: true,
+      })
+    ).toBe("es-ES");
+
+    expect(
+      resolveSurveyLanguage({
+        languages,
+        browserLanguageCodes: ["es-MX"],
+        autoSelectLanguage: false,
+      })
+    ).toBe("default");
+
+    expect(
+      resolveSurveyLanguage({
+        languages,
+        browserLanguageCodes: ["fr-CA"],
+        autoSelectLanguage: true,
+      })
+    ).toBe("default");
+  });
+
+  test("supports strict unmatched explicit language behavior", () => {
+    expect(
+      resolveSurveyLanguage({
+        languages,
+        explicitLanguageCode: "fr",
+        browserLanguageCodes: ["es-MX"],
+        autoSelectLanguage: true,
+        unmatchedExplicitLanguageBehavior: "undefined",
+      })
+    ).toBeUndefined();
+  });
+});

packages/types/surveys/language.ts

@@ -0,0 +1,108 @@
+interface TSurveyLanguageLike {
+  default?: boolean | null;
+  enabled?: boolean | null;
+  language: {
+    code: string;
+    alias?: string | null;
+  };
+}
+
+interface ResolveSurveyLanguageInput<T extends TSurveyLanguageLike> {
+  languages: T[];
+  explicitLanguageCode?: string;
+  browserLanguageCodes?: string[];
+  autoSelectLanguage?: boolean | null;
+  unmatchedExplicitLanguageBehavior?: "fallback" | "undefined";
+}
+
+export const normalizeLanguageCode = (languageCode: string): string =>
+  languageCode.trim().split(";")[0].trim().replace("_", "-").toLowerCase();
+
+const getBaseLanguageCode = (languageCode: string): string =>
+  normalizeLanguageCode(languageCode).split("-")[0];
+
+const getSelectableLanguageCode = (surveyLanguage: TSurveyLanguageLike): string | undefined => {
+  if (surveyLanguage.default) return "default";
+  if (!surveyLanguage.enabled) return undefined;
+  return surveyLanguage.language.code;
+};
+
+const findExactLanguageMatch = <T extends TSurveyLanguageLike>(
+  languages: T[],
+  languageCode: string
+): string | undefined => {
+  const normalizedLanguageCode = normalizeLanguageCode(languageCode);
+
+  const selectedLanguage = languages.find((surveyLanguage) => {
+    return (
+      normalizeLanguageCode(surveyLanguage.language.code) === normalizedLanguageCode ||
+      (surveyLanguage.language.alias
+        ? normalizeLanguageCode(surveyLanguage.language.alias) === normalizedLanguageCode
+        : false)
+    );
+  });
+
+  return selectedLanguage ? getSelectableLanguageCode(selectedLanguage) : undefined;
+};
+
+const findLooseLanguageMatch = <T extends TSurveyLanguageLike>(
+  languages: T[],
+  languageCode: string
+): string | undefined => {
+  const baseLanguageCode = getBaseLanguageCode(languageCode);
+
+  for (const surveyLanguage of languages) {
+    const selectableLanguageCode = getSelectableLanguageCode(surveyLanguage);
+    if (!selectableLanguageCode) continue;
+
+    const languageBaseCode = getBaseLanguageCode(surveyLanguage.language.code);
+    const aliasBaseCode = surveyLanguage.language.alias
+      ? getBaseLanguageCode(surveyLanguage.language.alias)
+      : undefined;
+
+    if (languageBaseCode === baseLanguageCode || aliasBaseCode === baseLanguageCode) {
+      return selectableLanguageCode;
+    }
+  }
+
+  return undefined;
+};
+
+export const matchSurveyLanguage = <T extends TSurveyLanguageLike>(
+  languages: T[],
+  languageCode: string
+): string | undefined => {
+  return findExactLanguageMatch(languages, languageCode) ?? findLooseLanguageMatch(languages, languageCode);
+};
+
+/**
+ * Resolves survey language precedence without coupling callers to a delivery channel:
+ * explicit language (URL or SDK/user setting) -\> browser languages when enabled -\> survey default.
+ */
+export const resolveSurveyLanguage = <T extends TSurveyLanguageLike>({
+  languages,
+  explicitLanguageCode,
+  browserLanguageCodes = [],
+  autoSelectLanguage,
+  unmatchedExplicitLanguageBehavior = "fallback",
+}: ResolveSurveyLanguageInput<T>): string | undefined => {
+  if (explicitLanguageCode) {
+    const explicitMatch = matchSurveyLanguage(languages, explicitLanguageCode);
+    if (explicitMatch) return explicitMatch;
+    return unmatchedExplicitLanguageBehavior === "undefined" ? undefined : "default";
+  }
+
+  if (!autoSelectLanguage) return "default";
+
+  for (const browserLanguageCode of browserLanguageCodes) {
+    const exactMatch = findExactLanguageMatch(languages, browserLanguageCode);
+    if (exactMatch) return exactMatch;
+  }
+
+  for (const browserLanguageCode of browserLanguageCodes) {
+    const looseMatch = findLooseLanguageMatch(languages, browserLanguageCode);
+    if (looseMatch) return looseMatch;
+  }
+
+  return "default";
+};

packages/types/surveys/types.ts

@@ -907,6 +907,7 @@ export const ZSurveyBase = z.object({
   projectOverwrites: ZSurveyProjectOverwrites.nullable(),
   styling: ZSurveyStyling.nullable(),
   showLanguageSwitch: z.boolean().nullable(),
+  autoSelectLanguage: z.boolean().nullish(),
   surveyClosedMessage: ZSurveyClosedMessage.nullable(),
   segment: ZSegment.nullable(),
   singleUse: ZSurveySingleUse.nullable(),

pnpm-lock.yaml

@@ -762,6 +762,10 @@ importers:
         version: 4.1.6(@opentelemetry/api@1.9.0)(@types/node@25.4.0)(@vitest/coverage-v8@4.1.6)(happy-dom@20.8.9)(jsdom@29.0.2(@noble/hashes@2.0.1))(vite@7.3.3(@types/node@25.4.0)(jiti@2.6.1)(lightningcss@1.32.0)(terser@5.46.2)(tsx@4.21.0)(yaml@2.8.3))
 
   packages/js-core:
+    dependencies:
+      '@formbricks/types':
+        specifier: workspace:*
+        version: link:../types
     devDependencies:
       '@formbricks/config-typescript':
         specifier: workspace:*
@@ -1038,6 +1042,12 @@ importers:
       '@formbricks/config-typescript':
         specifier: workspace:*
         version: link:../config-typescript
+      '@vitest/coverage-v8':
+        specifier: 4.1.6
+        version: 4.1.6(vitest@4.1.6)
+      vitest:
+        specifier: 4.1.6
+        version: 4.1.6(@opentelemetry/api@1.9.1)(@types/node@25.6.2)(@vitest/coverage-v8@4.1.6)(happy-dom@20.8.9)(jsdom@29.0.2(@noble/hashes@2.0.1))(vite@8.0.12(@types/node@25.6.2)(esbuild@0.27.7)(jiti@2.6.1)(terser@5.47.1)(tsx@4.21.0)(yaml@2.9.0))
 
   packages/vite-plugins:
     devDependencies: