Most of the strings specified in presentation rules and visible to the end user can be localized.

The library uses a simplified i18next JSON format - it only supports simple key-value pairs (including nesting) without plurals or interpolation.

On the frontend

All responses to requests made through the frontend's PresentationManager are automatically localized, assuming all required assets are properly set up. @itwin/presentation-frontend relies on IModelApp.localization to do the translations. All Presentation localized strings are defined in locale files located at the public folder from @itwin/presentation-common - consumers must ensure these locale files are placed at a location known to IModelApp.localization. See Localization in iTwin.js page for more details.

On the backend

In the case of only using the backend, consumers must provide a localization function PresentationManagerProps.getLocalizedString when initializing the presentation backend.

The localization function should translate the following strings:

List of translatable strings
  • @Presentation:label.notSpecified@
  • @Presentation:label.other@
  • @Presentation:label.varies@
  • @Presentation:label.multipleInstances@
  • @Presentation:field.label@
  • @Presentation:selectedItems.categoryLabel@
  • @Presentation:selectedItems.categoryDescription@

Example for providing the localization function:

function getLocalizedStringExample(key: string) {
  // implementation...

const presentationBackendProps: PresentationProps = {
  getLocalizedString: (key) => getLocalizedStringExample(key),


Localization in presentation rulesets

The strings in presentation rule sets can be localized by using the following format: @LocalizationNamespace:StringId@. Additionally, you can use multiple localized pieces in one string, e.g. Concat_@Namespace:String1@_and_@Namespace:String2@. Such strings are then localized using IModelApp.localization API using identifier specified between the @ characters, e.g. LocalizationNamespace:StringId for @LocalizationNamespace:StringId@.

Last Updated: 13 May, 2024