Localization

The API Reference can render its UI in different languages and writing directions. This localizes the interface chrome — search, navigation, sidebar, schema labels, operation sections, response examples, developer tools, and action buttons.

Note: This does not translate the content of your OpenAPI document (summaries, descriptions, tags, or examples). For localized content, provide a localized OpenAPI document/source.

Built-in locales

API Reference and API Client ship translations for the following locales. Missing keys fall back to English (en).

• en — English
• ru — Russian
• es — Spanish
• fr — French
• de — German
• zh-CN — Simplified Chinese
• ar — Arabic (renders right-to-left by default)
• pt — Portuguese

Configuration

Pass a localization object to your API Reference configuration:

Type: { locale?: string, direction?: 'ltr' | 'rtl' | 'auto', translations?: object }

Default: { locale: 'en', direction: 'ltr' }

{
  localization: {
    locale: 'de',
  },
}

locale

The locale used for the built-in UI translations. Regional values are accepted and fall back to the base language — for example es-MX resolves to es, and zh-Hans resolves to zh-CN. Unknown locales fall back to English.

direction

The text direction: 'ltr', 'rtl', or 'auto'. With 'auto' (or when omitted) the direction is derived from the locale, so Arabic and other right-to-left languages render correctly without extra configuration. Set it explicitly to override.

{
  localization: {
    locale: 'ar',
    direction: 'auto', // renders right-to-left
  },
}

translations

Override individual labels, or add your own language on top of a built-in locale. Values are merged with the selected locale and the English fallback, so you only need to specify the keys you want to change.

{
  localization: {
    locale: 'es',
    translations: {
      operation: {
        testRequest: 'Enviar solicitud de prueba',
        responses: 'Respuestas',
      },
    },
  },
}

API Client

The embedded API Client accepts overrides under localization.translations.apiClient. Pass them to API Reference alongside your reference translations; they also apply to the client opened by Test Request. Updates to the reference configuration update the client labels, locale, and direction.

The API Client supports the same built-in locales listed above. Setting localization: { locale: 'de' } translates both the reference and its embedded client without custom strings. Overrides merge on top of the selected language, and regional locale values use the same fallback rules.

{
  localization: {
    locale: 'de',
    translations: {
      operation: { testRequest: 'Anfrage testen' },
      apiClient: {
        addressBar: {
          send: 'Senden',
          sendRequest: '{method}-Anfrage an {url} senden',
        },
        requestBlock: {
          authentication: 'Authentifizierung',
          headers: 'Kopfzeilen',
          queryParameters: 'Abfrageparameter',
          requestBody: 'Anfragetext',
        },
        responseBlock: { response: 'Antwort' },
        responseEmpty: { sendRequest: 'Anfrage senden' },
        sectionFilter: { all: 'Alle', headers: 'Kopfzeilen', body: 'Inhalt' },
      },
    },
  },
}

Use the same localization object in createApiClientModal({ options: { localization }, ... }) or the standalone Operation component's options prop. modal.updateOptions({ localization }) updates an existing modal. Custom Vue hosts can call provideLocalization from @scalar/api-client/features/localization in their setup function to localize client components in that subtree.

ApiClientTranslations, exported from @scalar/types/api-reference, lists the available keys. The English dictionary is in packages/api-client/src/v2/features/localization/translations.ts. The other built-in dictionaries are in packages/api-client/src/v2/features/localization/locales. Preserve placeholders such as {method}, {url}, and {name} in translated messages. Translation values render as text. Request URLs, HTTP methods, MIME types, credentials, and content from your API description remain unchanged.

Unavailable code samples

The status shown when a linked SDK sample is missing follows the selected locale in both API Reference layouts and the API Client. Override operation.codeSampleUnavailable for the API Reference or apiClient.requestCodeSnippet.unavailable for the API Client in localization.translations.

When using the standalone CodeExample component or createCodeExample, pass codeSampleUnavailable to supply localized status text. It defaults to English.