Regarding your stack : Internet server with Windows : I really think Windows really have no added value in this area. Installing a DBMS like MySQL or MSSQL : you might be interested in NoSQL kind of database as you probably have limited relations between your data. I think some database also integrate out of the shelves a Rest or Curl API, at least that used to be the case with couchDb for instance No direct access to the database from outside for safety reasons Instead writing an API that runs on the server and allows indirect DB Access via predefined (HTTP?) Requests. if possible, aim for HTTPS right from the start. Regarding the authentification, for a pet project I have been relying on Wordpress to manage user management through REST, I am not sure tough it is actually a good solution but at least it is cheap and quite easy to set up.

@tansgumus said in REST API client: RESTful API Hello, how did you solve it, I also want to use RESTful API in QT.

@JonB I also thought it could be due to cache, so I ran the manager.clearConnectionCache command but that does not help. I also tried to find a way to force it to provide credentials but I have not found any other way to do so. But that was when I still wasn't sure that the server actually requests this, but since I now know that the server sends the www-authenticate request I know the error is in my applicaton or in qt. Yes, I get the QNetworkReply::AuthenticationRequiredError. So weird that I get that error and not the authenticationRequired signal.