1. Open this file for editing: <SMARTIDHOME>/docker/compose/selfservice/docker-compose.yml.

2. Set the supported languages and the default language to be used. This is done in the CONFIG_JSON environment variable, see Set properties for Smart ID Self-Service.

   Set language for Self-Service

   "languages": {
       "supportedLanguages": [ "en", "de", "ar", "sv", "fr" ],
       "defaultLanguage": "en"
   }

3. Set the supported languages and the default language to be used. This is done in the CONFIG_JSON environment variable, see Set properties for Smart ID Self-Service. See ISO 639-1 for a valid list of language codes.

1. If the container is not running, start it (it does not matter if the container ends up unhealthy and the application does not work, as long as the container is up).

2. Copy the original files from the container to your host machine. 

   docker cp smartid-selfservice:/usr/local/tomcat/webapps/ROOT/assets/i18n <SMARTIDHOME>/docker/compose/selfservice/config/translations

3. Remove the files for the translations you do not support.

4. Add <SMARTIDHOME>/docker/compose/selfservice/config/translations as volume to <SMARTIDHOME>/docker/compose/selfservice/docker-compose.yml.

   - "./config/translations:/usr/local/tomcat/webapps/ROOT/assets/custom-i18n:rw"

5. (Optional) Run docker-compose up -d to recreate the container, so that the new translation files are loaded.

To modify existing translations, edit your files in <SMARTIDHOME>/docker/compose/identitymanager/config/translations 

1. In each file, keep only the keys you want to change, and modify their values.
2. Run docker-compose up -d if you did not run step 5 in "Extract translation files" above, else run docker-compose restart.

To add a translation file for a language that is not available by default, follow these steps:

1. Create a new translation file in <SMARTIDHOME>/docker/compose/selfservice/config/translations following this naming convention <language_code>.json (See ISO 639-1 for a valid list of language codes).
2. Copy the contents of the extracted en.json into your newly created file in order to have the keys. (See "Extract translation files" above.)

3. Edit the file you created and translate the values to your language.

4. Run docker-compose up -d if you did not run step 5 in "Extract translation files" above, else run docker-compose restart.