Lingo - Translator for Confluence supports DeepL translator. To use DeepL as a machine translation service, you require a DeepL Free or Pro subscription to obtain an API key. Refer to https://www.deepl.com/en/pro#developer for further details.
When you get a valid Free or Pro DeepL API, open the app configuration, add a key and save it. After the right DeepL key is added, users can define languages and permissions.