Yes, t3api supports multilanguage applications! If you would like to do request in language other than default you just need to add request header X-Locale with value set to identifier of expected language. Identifier means languageId from your site’s config.yaml.

Here is an example configuration of multilanguage page.

    title: English
    enabled: true
    languageId: '0'
    base: /
    typo3Language: default
    locale: en_US.UTF-8
    iso-639-1: en
    navigationTitle: ''
    hreflang: en-US
    direction: ltr
    flag: en-us-gb
    title: German
    enabled: true
    languageId: '1'
    base: /de/
    typo3Language: de
    locale: de_DE.UTF-8
    iso-639-1: de
    navigationTitle: ''
    hreflang: de-DE
    direction: ltr
    fallbackType: strict
    flag: de

According to example above: Sending X-Locale: 0 or not sending X-Locale header at all means that it will be processed in English. If request would include header X-Locale: 1 then it will be processed in German.


t3api respects fallbackType set in site’s configuration.

It is possible to customize name of the language header inside ext_localconf.php:

$GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['t3api']['languageHeader'] = 'My-Header-Name';