I am pretty sure that those URLs must not be used by us, i.e. their (unpaid) usage is not wanted by Language Tooler GmbH. The "Public HTTP Proofreading API" page (https://dev.languagetool.org/public-http-api) explicitly states > We offer a simple HTTPS REST-style service that anybody can use to check texts with LanguageTool. The only public endpoint is the following one - do not send your requests to any other endpoints you might find in the homepage’s HTML code or elsewhere: > > https://api.languagetool.org/v2/check Obviously, using the URL https://api.languagetoolplus.com/v2/check violates this condition.