/v3/languages endpoint, which returns language support per resource along with feature availability (e.g. formality, glossary, auto-detection). The legacy /v2/languages endpoint is also available but deprecated.
API Supported Languages
Style rules are supported for the following target languages:
de, en, es, fr, it, ja, ko, and zh. For more details, see the Style Rules API documentation. Writing style and tone availability for /write/rephrase can also be retrieved via GET /v3/languages?resource=write.