> ## Documentation Index
> Fetch the complete documentation index at: https://sdk.libratech.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Locales

> Ship only the languages you need and switch them at runtime

The SDK bundle ships only the `en-US` translations to keep the default download small. Any other locale is published as a separate side-loadable file under `dist/locales/<code>.{js,umd.cjs}`. Load only the languages you need; they fetch in parallel with the main bundle, so you pay download cost roughly equal to `max(main, locale)` instead of `main + all locales`.

Both `Libra.init({ locale })` and `Libra.setLocale(locale)` throw synchronously when called with an unregistered locale, so the failure surfaces at the call site instead of silently rendering English. Browser-detected fallback (when `locale` is unset at init) still resolves to `en-US` if no registered locale matches.

## Supported locales

`en-US` · `de-DE` · `de-CH` · `pl-PL` · `nl-NL` · `nl-BE` · `fr-BE` · `fr-CH` · `it-IT` · `it-CH` · `ro-RO` · `hu-HU` · `cs-CZ` · `sk-SK`

<Frame caption="The same session after Libra.setLocale('de-DE'): the interface is German, the conversation is untouched">
  <img src="https://mintcdn.com/libra-sdk/urMcTJk7LWyFarvE/assets/images/sdk/locale-de.png?fit=max&auto=format&n=urMcTJk7LWyFarvE&q=85&s=bf150e4db10d7ace054320bcd5075c4a" alt="Libra widget in German showing '12 zitierte Quellen' and Kopieren / Neu generieren / Exportieren actions above the same answer" width="360" data-path="assets/images/sdk/locale-de.png" />
</Frame>

## npm consumers

Import the locale defaults and pass them to `Libra.init({ locales })`:

```javascript theme={null}
import { Libra } from '@libra/sdk';
import deDE from '@libra/sdk/locales/de-DE';
import frCH from '@libra/sdk/locales/fr-CH';

Libra.init({
  productId: 'wko_de',
  locale: 'de-DE',
  locales: [deDE, frCH]
});
```

## CDN consumers: classic script tag

Each locale's UMD bundle self-registers into `window.__libraLocales__`, which `Libra.init()` drains automatically; no `locales` field needed:

```html theme={null}
<script src="https://cdn.wolterskluwer.io/wk/libra-sdk/<VERSION>/libra.umd.js"></script>
<script src="https://cdn.wolterskluwer.io/wk/libra-sdk/<VERSION>/locales/de-DE.umd.js"></script>
<script src="https://cdn.wolterskluwer.io/wk/libra-sdk/<VERSION>/locales/fr-CH.umd.js"></script>
<script>
  const { Libra } = window.Libra;
  Libra.init({ locale: 'de-DE' });
</script>
```

The order of the locale script tags relative to the main `libra.umd.js` does not matter as long as all of them load before `Libra.init()` is called.

## CDN consumers: ES module

Load the SDK and the locales you need in parallel, then pass the defaults to `init()`:

```html theme={null}
<script type="module">
  const cdnBase = 'https://cdn.wolterskluwer.io/wk/libra-sdk/<VERSION>';

  const [{ Libra }, deDE, frCH] = await Promise.all([
    import(`${cdnBase}/libra.js`),
    import(`${cdnBase}/locales/de-DE.js`).then((m) => m.default),
    import(`${cdnBase}/locales/fr-CH.js`).then((m) => m.default)
  ]);

  Libra.init({
    productId: 'wko_de',
    locale: 'de-DE',
    locales: [deDE, frCH]
  });
</script>
```

The `Promise.all` ensures the locale bundles fetch in parallel with the SDK; overall wall-clock load time is roughly `max(libra.js, largest locale)` instead of the sum.

## Switching at runtime

`Libra.setLocale(locale)` updates the widget's UI language at runtime. Translated strings re-render in place, the chat session is preserved, and the locale is persisted in the iframe's `localStorage`. The target locale must have been registered at init time.

```javascript theme={null}
Libra.setLocale('de-DE');
```

The Auth0 login popup follows the configured locale as well.