Language Support

The resources of the IBM Application Gateway (IAG) container have been translated into a number of different languages. These resources include:

  1. Error messages which appear on the console of the IAG container;
  2. Web responses, including error and management responses, which are generated by the IAG container and returned to the client.

Character Encoding

Please note that the IAG container requires that all configuration YAML files are encoded in UTF-8 (8-bit Unicode Transformation Format). The easiest way to ensure that the YAML files are encoded correctly is to only create/edit the configuration files in environments which have been configured with a UTF-8 based locale (for example: "en_US.utf8" or "ja_JP.utf8").

Supported Languages

IAG provides translated pages and messages for the following languages:

LanguageLanguage code
Brazilian Portuguesept_BR
Chinese (Simplified)zh_CN
Chinese (Traditional)zh_TW

IAG console error messages

The language which is used when sending error messages to the console of the container is controlled by the 'LANG' environment variable. This environment variable should be set to match a supported language code when deploying the container.

For example, to display error messages in Japanese the LANG environment should be set as:


See Deploying to Kubernetes and Deploying to Docker for more information on how to set environment variables when deploying the IAG container.



  • Only a single language can be specified when deploying the IAG container.
  • The container will default to using English error messages if no language, or an unsupported language, is specified.

Management and error responses

Default IAG responses

The software can return management and error responses in the preferred language of the client. The language which is used in the response is determined by the 'Accept-Language' header found in the HTTP request.

As per the standard, the Accept-Language header can include more than one language, with each additional language separated by a comma. For example:

Accept-Language: pt-BR,es,en-US

The order in which the values appear in the header will determine the priority of the language. IAG will check each language in the list until it finds a supported language.

When searching for a matching language the software will automatically strip subtags from the language string in an attempt to match one of the supported languages. For example, a language tag of 'fr-FR' will be matched to the 'fr' language code.



  • If IAG receives a request with no 'Accept-Language' header it will default to English
  • IAG always returns the UTF-8 character set to the user, regardless of the value of the 'Accept-Charset' HTTP header in the request
  • IAG does not recognize the quality value attribute of the 'Accept-Language' header. The listed order of languages in the header will determine the order of priority.

Creating custom management and error pages

The default management and error pages for IAG supported languages can be replaced with custom pages. See Defining Custom Responses for more information on creating custom IAG response pages.