# Internationalization

In this chapter the openHAB support for internationalization is described.

# Folder and File Structure

All texts can be internationalized by using Java i18n properties files. For each language a specific file with a postfix notation is used. The postfix consists of a language code and an optional region code (country code).

Format:     any_<language-code>_<country-code>.properties
Example:    any_de_DE.properties

The language code is either two or three lowercase letters that are conform to the ISO 639 standard. The region code (country code) consists of two uppercase letters that are conform to the ISO 3166 standard or to the UN M.49 standard.

The search order for those files is the following:


You can find detailed information about Java internationalization support and a list of the ISO 639 and ISO 3166 codes at The Java Tutorials (opens new window) page.

The properties files have to be placed in the following directory of the bundle:


Example files:

|---- i18n
|------- acmeweather.properties
|------- acmeweather_de.properties
|------- acmeweather_de_DE.properties
|------- acmeweather_fr.properties

# Internationalize Binding XML files

In openHAB a binding developer has to provide different XML files. In these XML files label and description texts must be specified. To Internationalize these texts Java I18N properties files must be defined.

For the binding definition and the thing types XML files openHAB defines a standard key scheme, that allows to easily reference the XML nodes. Inside the XML nodes the text must be specified in the default language English. Typically all texts for a binding are put into one file with name of the binding, but they can also be split into multiple files.

# Binding Definition

The following snippet shows the binding XML file of an ACME Weather Binding and its language file that localizes the binding name and description for the German language.

XML file (binding.xml):

<binding:binding id="acmeweather">
    <name>ACME Weather Binding</name>
    <description>The ACME Weather Binding requests the ACME Weather Service
        to show the current temperature, humidity and pressure.</description>

Language file (acmeweather_de.properties):

binding.acmeweather.name =ACME Wetter Binding
binding.acmeweather.description = Das ACME Wetter Binding stellt verschiedene Wetterdaten wie die Temperatur, die Luftfeuchtigkeit und den Luftdruck für konfigurierbare Orte vom ACME Wetterdienst bereit.

So the key for referencing the name of a binding is binding.<binding-id>.name and binding.<binding-id>.description for the description text.

# Thing Types

The following snippet shows an excerpt of the thing type definition XML file of an ACME Weather Binding and its language file that localizes labels and descriptions for the German language.

XML file (thing-types.xml):

<thing:thing-descriptions bindingId="acmeweather">
    <thing-type id="weather">
        <label>Weather Information</label>
        <description>Provides various weather data from the ACME Weather Service.</description>
            <channel id="precipitation" typeId="precipitation" />
            <channel id="temperature" typeId="temperature" />
            <channel id="minTemperature" typeId="temperature">
                <label>Min. Temperature</label>
                <description>Minimum temperature in degrees Celsius (metric) or Fahrenheit (imperial).</description>
            <parameter name="location" type="text">
                <description>Location for the weather information. Syntax is WOEID, see https://en.wikipedia.org/wiki/WOEID.</description>
    <channel-type id="precipitation">
        <description>Current precipitation (dry, rain, snow).</description>
        <state readOnly="true" pattern="%s">
                <option value="dry">dry</option>
                <option value="rain">rain</option>
                <option value="snow">snow</option>
    <channel-type id="temperature">
        <description>Current temperature in degrees Celsius (metric) or Fahrenheit (imperial).</description>
        <state readOnly="true" pattern="%d Value" />
            <parameter name="unit" type="text" required="true">
                <label>Temperature unit</label>
                <description>Select the temperature unit.</description>
                    <option value="C">Degree Celsius</option>
                    <option value="F">Degree Fahrenheit</option>
    <channel-type id="cmd-channel">
        <label>Device Commands</label>
        <description>Send one of the defined command options to the device.</description>
                <option value="RESET">Reset</option>
                <option value="CMD_1">Command 1</option>
                <option value="CMD_2">Command 2</option>

Language file (acmeweather_de.properties):

thing-type.acmeweather.weather.label = Wetterinformation
thing-type.acmeweather.weather.description = Stellt verschiedene Wetterdaten vom ACME Wetterdienst bereit.

thing-type.config.acmeweather.weather.location.label = Ort
thing-type.config.acmeweather.weather.location.description = Ort der Wetterinformation. Syntax ist WOEID, siehe https://en.wikipedia.org/wiki/WOEID.

channel-type.acmeweather.precipitation.label = Niederschlag
channel-type.acmeweather.precipitation.description = Aktueller Niederschlag (Trocken, Regen, Schnee).
channel-type.acmeweather.precipitation.state.option.dry = Trocken
channel-type.acmeweather.precipitation.state.option.rain = Regen
channel-type.acmeweather.precipitation.state.option.snow = Schnee

channel-type.acmeweather.temperature.label = Temperatur
channel-type.acmeweather.temperature.description = Aktuelle Temperatur in Grad Celsius (Metrisch) oder Grad Fahrenheit (US).
channel-type.acmeweather.temperature.state.pattern = %d Wert

thing-type.acmeweather.weather.channel.minTemperature.label = Min. Temperatur
thing-type.acmeweather.weather.channel.minTemperature.description = Minimale Temperatur in Grad Celsius (Metrisch) oder Grad Fahrenheit (US).

channel-type.config.acmeweather.temperature.unit.label = Temperatur Einheit
channel-type.config.acmeweather.temperature.unit.description = Auswahl der gewünschten Temperatur Einheit.
channel-type.config.acmeweather.temperature.unit.option.C = Grad Celsius
channel-type.config.acmeweather.temperature.unit.option.F = Grad Fahrenheit

channel-type.acmeweather.cmd-channel.command.option.RESET = Reset Device
channel-type.acmeweather.cmd-channel.command.option.CMD1 = Command one
channel-type.acmeweather.cmd-channel.command.option.CMD2 = Command two

So the key for referencing a label of a defined thing type is thing-type.<binding-id>.<thing-type-id>.label. A label of a channel type can be referenced with channel-type.<binding-id>.<channel-type-id>.label and a label of a channel definition with thing-type.<binding-id>.<thing-type-id>.channel.<channel-id>.label. And finally the config description parameter key is thing-type.config.<binding-id>.<thing-type-id>.<parameter-name>.label or channel-type.config.<binding-id>.<channel-type-id>.<parameter-name>.label.

The following snippet shows an excerpt of the thing type definition XML file of the Weather Underground Binding and its language file that localizes labels and descriptions for the French language.

XML file (thing-types.xml):

<thing:thing-descriptions bindingId="weatherunderground">

    <thing-type id="weather">
        <label>Weather Information</label>
        <description>Provides various weather data from the Weather Underground service</description>

            <channel-group id="current" typeId="current" />
            <channel-group id="forecastTomorrow" typeId="forecast">
                <label>Weather Forecast Tomorrow</label>
                <description>This is the weather forecast for tomorrow.</description>
            <channel-group id="forecastDay2" typeId="forecast">
                <label>Weather Forecast Day 2</label>
                <description>This is the weather forecast in two days.</description>

            <parameter name="apikey" type="text" required="true">
                <label>API Key</label>
                <description>API key to access the Weather Underground service.</description>
            <parameter name="location" type="text" required="true">
                <label>Location of Weather Information</label>
                <description>Multiple syntaxes are supported. Please read the binding documentation for more information.</description>
            <parameter name="language" type="text" required="false">
                <description>Language to be used by the Weather Underground service.</description>
                    <option value="EN">English</option>
                    <option value="FR">French</option>
                    <option value="DL">German</option>
            <parameter name="refresh" type="integer" min="5" required="false" unit="min">
                <label>Refresh interval</label>
                <description>Specifies the refresh interval in minutes.</description>

    <channel-group-type id="current">
        <label>Current Weather</label>
        <description>This is the current weather.</description>
            <channel id="conditions" typeId="currentConditions" />
            <channel id="temperature" typeId="temperature" />

    <channel-group-type id="forecast">
        <label>Weather Forecast</label>
        <description>This is the weather forecast.</description>
            <channel id="temperature" typeId="temperature">
                <description>Forecasted temperature</description>
            <channel id="maxTemperature" typeId="maxTemperature" />

    <channel-type id="currentConditions">
        <label>Current Conditions</label>
        <description>Weather current conditions.</description>
        <state readOnly="true" pattern="%s"></state>

    <channel-type id="temperature">
        <description>Current temperature.</description>
        <state readOnly="true" pattern="%.1f" />
            <parameter name="SourceUnit" type="text" required="true">
                <label>Temperature Source Unit</label>
                <description>Select the temperature unit provided by the Weather Underground service.</description>
                    <option value="C">Degree Celsius</option>
                    <option value="F">Degree Fahrenheit</option>

    <channel-type id="maxTemperature">
        <label>Maximum Temperature</label>
        <description>Maximum temperature.</description>
        <state readOnly="true" pattern="%.1f" />
            <parameter name="SourceUnit" type="text" required="true">
                <label>Maximum Temperature Source Unit</label>
                <description>Select the maximum temperature unit provided by the Weather Underground service.</description>
                    <option value="C">Degree Celsius</option>
                    <option value="F">Degree Fahrenheit</option>


Language file (weatherunderground_fr.properties):

# binding
binding.weatherunderground.name = Extension WeatherUnderground
binding.weatherunderground.description = L'extension Weather Underground interroge le service Weather Underground pour récupérer des données météo.

# thing types
thing-type.weatherunderground.weather.label = Informations météo
thing-type.weatherunderground.weather.description = Présente diverses données météo fournies par le service Weather Underground.

# thing type configuration
thing-type.config.weatherunderground.weather.apikey.label = Clé d'accès
thing-type.config.weatherunderground.weather.apikey.description = La clé d'accès au service Weather Underground.
thing-type.config.weatherunderground.weather.location.label = Emplacement des données météo
thing-type.config.weatherunderground.weather.location.description = Plusieurs syntaxes sont possibles. Merci de consulter la documentation de l'extension pour plus d'information.
thing-type.config.weatherunderground.weather.language.label = Langue
thing-type.config.weatherunderground.weather.language.description = La langue à utiliser par le service Weather Underground.
thing-type.config.weatherunderground.weather.language.option.EN = Anglais
thing-type.config.weatherunderground.weather.language.option.FR = Français
thing-type.config.weatherunderground.weather.language.option.DL = Allemand
thing-type.config.weatherunderground.weather.refresh.label = Fréquence de rafraîchissement
thing-type.config.weatherunderground.weather.refresh.description = La fréquence de rafraîchissement des données en minutes.

# channel group types
channel-group-type.weatherunderground.current.label = Météo actuelle
channel-group-type.weatherunderground.current.description = La météo actuelle.
channel-group-type.weatherunderground.forecast.label = Météo prévue
channel-group-type.weatherunderground.forecast.description = La météo prévue.

# channel groups
thing-type.weatherunderground.weather.group.forecastTomorrow.label = Météo de demain
thing-type.weatherunderground.weather.group.forecastTomorrow.description = La météo prévue demain.
thing-type.weatherunderground.weather.group.forecastDay2.label = Météo dans 2 jours
thing-type.weatherunderground.weather.group.forecastDay2.description = La météo prévue dans 2 jours.

# channel types
channel-type.weatherunderground.currentConditions.label = Conditions actuelles
channel-type.weatherunderground.currentConditions.description = Les conditions météo actuelles.
channel-type.weatherunderground.temperature.label = Température
channel-type.weatherunderground.temperature.description = La température actuelle.
channel-type.weatherunderground.maxTemperature.label = Température maximale
channel-type.weatherunderground.maxTemperature.description = La température maximale.

# channels inside a channel group type
channel-group-type.weatherunderground.current.channel.temperature.label = Température
channel-group-type.weatherunderground.current.channel.temperature.description = La température prévue.

# channel type configuration
channel-type.config.weatherunderground.temperature.SourceUnit.label = Unité de température
channel-type.config.weatherunderground.temperature.SourceUnit.description = Choix de l'unité de température fournie par le service Weather Underground pour la température actuelle.
channel-type.config.weatherunderground.temperature.SourceUnit.option.C = Degrés Celsius
channel-type.config.weatherunderground.temperature.SourceUnit.option.F = Degrés Fahrenheit
channel-type.config.weatherunderground.maxTemperature.SourceUnit.label = Unité de température maximale
channel-type.config.weatherunderground.maxTemperature.SourceUnit.description = Choix de l'unité de température fournie par le service Weather Undergroundde pour la température maximale.
channel-type.config.weatherunderground.maxTemperature.SourceUnit.option.C = Degrés Celsius
channel-type.config.weatherunderground.maxTemperature.SourceUnit.option.F = Degrés Fahrenheit

So the label of a channel group type can be referenced with channel-group-type.<binding-id>.<channel-group-type-id>.label and the label of a channel group definition with thing-type.<binding-id>.<thing-type-id>.group.<channel-group-id>.label. A label of a channel definition inside a channel group type can be translated with channel-group-type.<binding-id>.<channel-group-type-id>.channel.<channel-id>.label.

# Discovery

A binding can provide localized labels for discovery results. Use any English label of your choice to create your DiscoveryResult:

            DiscoveryResult discoveryResult = DiscoveryResultBuilder.create(thingUID).withProperties(properties)
                    .withBridge(bridgeUID).withLabel("Local Weather And Forecast").build();

In this case it is mandatory to define a language file for the English language. Add the same label to this default properties file (e.g. darksky.properties):

 # discovery result
 discovery.darksky.weather-and-forecast.api.local.label = Local Weather And Forecast

The pattern follows this pattern: discovery.<binding-id>.<thing-type-id>.<bridge-id>.<thing-id>.label = <your-translated-label>. The <bridge-id> is optional and only needed if your Binding implements a Bridge / Thing structure. Add as much translations as you like in separate Language files (e.g. darksky_de.properties):

# discovery result
discovery.darksky.weather-and-forecast.api.local.label = Lokales Wetter und Wettervorhersage

# Using custom Keys

In addition to the default keys the developer can also specify custom keys inside the XML file. But with this approach the XML file cannot longer contain the English texts. So it is mandatory to define a language file for the English language. The syntax for custom keys is @text/<key> [params]. The keys are unique across the whole bundle, so a constant can reference any key in all files inside the OH-INF/i18n folder.

The following snippet shows a binding XML that uses custom keys:

XML file (addon.xml):

<addon:addon id="acmeweather">

Language file (acmeweather_en.properties):

# add-on

addon.acmeweather.name = ACME Weather Binding
addon.acmeweather.description = Binding for ACME Weather

# thing status descriptions

offline.communication-error = The ACME Weather API is currently not available. Error {0}

Language file (acmeweather_de.properties):

# add-on

addon.acmeweather.name = ACME Wetter Binding
addon.acmeweather.description = Binding für ACME Wetter

# thing status descriptions

offline.communication-error = Die ACME Wetter API ist zur Zeit nicht verfügbar. Fehler {0}

The custom keys are a very good practice to translate bundle dependent error messages.

updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR, "@text/offline.communication-error [\"EX-500\"]");

# Generating I18N properties file

To automatically generate an I18N properties file from XML files, the following command can be run:

mvn i18n:generate-default-translations

This tool can also be used to update an existing file. Custom texts will be preserved when doing this.

# I18n Text Provider API

To programmatically resolve texts for certain languages openHAB provides the OSGi service TranslationProvider. The service parses every file inside the OH-INF/i18n folder and caches all texts. A localized text can be retrieved via the method getText(Bundle bundle, String key, String default, Locale locale) (or via the method getText(Bundle bundle, String key, String default, Locale locale, Object... arguments) if additional arguments are to be injected into the localized text), where bundle must be the reference to the bundle, in which the file is stored. The BundleContext from the Activator provides a method to get the bundle.

String text = i18nProvider.getText(bundleContext.getBundle(), "my.key", "DefaultValue", Locale.GERMAN);

# Locale Provider

To programmatically fetch the locale used by the openHAB system an OSGi service LocaleProvider is offered. The service contains a getLocale() method that can be used to choose a configurable locale.

# Getting Thing Types and Binding Definitions in different languages

Thing types can be retrieved through the ThingTypeRegistry OSGi service. Every method takes a Locale as last argument. If no locale is specified the thing types are returned for the default locale which is determined by using the LocaleProvider, or the default text, which is specified in the XML file, if no language file for the default locale exists.

The following snippet shows how to retrieve the list of Thing Types for the German locale:

List<ThingType> thingTypes = thingTypeRegistry.getThingTypes(Locale.GERMAN);

If one binding supports the German language and another does not, it might occur that the languages of the returned thing types are mixed.

For Binding Info and ConfigDescription, the localized objects can be retrieved via the BindingInfoRegistry and the ConfigDescriptionRegistry in the same manner as described for Thing Types.

# Managing translations

Localization is managed with the cloud service Crowdin (opens new window) where translators can contribute translations in different languages.

This is the process:

  • Texts in the original language (English) are provided (with the corresponding code) in pull requests.
  • When a pull request is merged, the texts will be automatically imported into Crowdin.
  • Texts can now be translated into multiple languages using Crowdin.
  • Once a day a pull request with updated translations is automatically created. Please note that all texts must be translated and approved in order to be included.
  • Maintainers will then merge these pull requests after verifying them (encoding, correctness of placeholder variables, accidentally removed texts, etc.).

Because of this process, translations should not be provided with pull requests as this can cause conflicts and ultimately overwritten/lost translations.